Getting really down trying to set boundaries

Keep your curtains shut for a week. Ignore the door and phone. Get dh to invite them when he is home. He needs to manage their behaviour not you.

I'm one of these unpopular people on MN who doesn't answer the door or phone if I don't want to, I will see someone look through the window, look them dead in the eye and go back to what I was doing and ignore them if I wasn't expecting them/it isn't convenient (pre pandemic now we have the yard locked down and it's bliss!). I got this way largely due to my abusive ex's parents doing exactly what you describe. Now I'm what my DH calls alternately a badass and a Sherman tank depending on his mood because I've zero fucks left to give. I spent years worrying about what others felt, letting them put their wants first and being made into a shadow of my self now I just won't do it. I've made my boundaries clear, phone/text first, if I can accommodate you I will, if you don't you can stand there until the cows come home not my problem.

I think you need to ask your dh to take over here. If you haven’t already, you need to make it crystal clear to him that you can’t continue to tolerate their behaviour. Spell out what is acceptable and what isn’t. And if he can’t get them to comply with your rules, what the consequences will be.
You’re not being unreasonable asking for a quick text before they turn up.
He needs to remind them that it’s in their control to follow the rules and if they choose to break them, they’re also choosing to not see their grandchild.
In the meantime, put a note on your door saying the baby’s sleeping, you’re working and not to knock.

net curtains. though they are no good if you have a window the other end of the room. and peering really close to them may let them see in.

frosted glass stick on stuff.

Having seen your update (I’m a slow thinker/typer), I think you need to look at alternative childcare, just in case. And try not to think they’ve got the upper hand because you need them. They want to see their grandchild.
But as pp say, it’s really up to your dh to sort this.

Is your dh supportive of you? When you said “we were talking about going into a support bubble” do you mean he was saying that? Trying to persuade you? If he doesn’t know how strongly you feel, then you need to make it crystal clear. If he does know, and he’s still trying to persuade you, then he’s your problem, not your in laws.
Without him standing up for you, you are bound to feel even more vulnerable. I can’t imagine having a tiny baby in these times but he should understand.

OP,
You need to communicate this to your husband.
Clearly.
I think unless he steps in and spells it out, this will continue.
You could just ignore the door but they sound horrendous.
It reads like harassment, because you have repeatedly asked them to do things and they just don't care.

If you imagine things are bad, using them for childcare will be so much worse.
They will do what they want, how they want.

You sound very stressed.
I think unless you speak very clearly to your husband and he has your back completely, I think you may find your marriage damaged and Wales will look even more attractive.

Your husband should be reiterating to them NOT to call without checking if it's convenient and you need to think about not answering the door. Close your curtains, nets etc., misting spray is easy and inexpensive.

This is the problem with childcare from family. You stand up to them and they refuse to do, what is a massive favour for you.

Put headphones on while you work so you can pretend you can't hear them? It's what I do when I'm sick of talking to people, or pretend to be asleep.

What is your DH doing to help sort out HIS parents?

They sound bloody awful.

Tell them you will no longer be available for 'ad hoc' visits. Then stop answering the door. Draw the curtains. Don't answer the phone.

My mum did this a lot - she'd turn up at my house with guests when I was working. After about the umpteenth time, I asked her not to do it and very politely asked that she phoned to agree a time when I could take a break from work. But she likes to play games, so she carried on doing it. First time I let her into the hall with her guest and then ushered her out after a few minutes. And repeated my request politely. Second time, I didn't let her through the door, but did pass her the ridiculous thing she asked for to justify the visit. Told her if she did it again, I would not answer the door. The next time, I just ignored her.
With my mum it's a powerplay. I have to be available on demand.
She then decided to up the ante and stopped calling round at all - she needed to teach me a lesson. On the few times she did have to call round for something, she would stand on the doorstep and refuse to cross the threshold unless I made a formal request for her to come in.
It's fucking ridiculous. We've gone from having a good relationship to a crap one because she can't accept that when I'm working from home, I have to work and can't host her and her friends. She'd rather go low contact with me than pick up a phone and agree a time to visit.
But you can't argue with batshit crazy.
So we see very little of each other anymore, but at least she's had the pleasure of knowing she's taught me a lesson.

YANBU OP. That would drive me mad and, as you say, how can you trust them when they ignore you? If you were to move closer to your family would your family be a childcare option?

1)They sound dreadful and are taking advantage of your good nature. I would also like to know what you do when people trample all over your attempts to set boundaries because mine are the same!
2)Support bubbles aren't just something you can opt in and out of whenever you feel like it. They're fixed aren't they?

It is fucking ridiculous. Not least because my brother also works from home, but she would never dream of dropping into his during work hours because he is a MAN with an IMPORTANT JOB.

I sympathise. My parents get very angry when i try to have a boundary.
People say "set boundaries!" But ime boundaries are forbidden in my family and will peovoke a row no matter how little i say. Im 50 and my parents act like they own me. Lc atm but they put that down to my beingso stressed and so "silly"

Lock the doors, dont answer if they knock/call, Put up nets/stick on frosted glass.
Consider answering just once a week and if that still doesnt work, you call them once a week and arrange somewhere such as a park to meet

You need a better/different option for childcare than these jokers.

Actually, they are YOUR HUSBANDS only source if childcare of you will also be working.

You need to make them his problem.

They are not listening to anything you say and doing exactly what they want. You have to stop this. I don't know why you agreed to do a bubble with them or did you DH agree because he's just used to it.
They are not your employers.
You have the right to say no to this and decide how often you see people.
The gifts are a way to make you feel beholden so that you can't then turn around and say but I asked you not to come.
Ask yourself What would happen if you said no to them? Whats the worst thing. Would they be angry? Cause a scene? Punish you by taking offense and turning the cold shoulder? At least that would give you some respite.
As they are not listening you could try to write, email them. Be consise and clear and don't couch it in apologies.
Say that You have wfh work to do in between baby's naps and you cannot have people dropping round without asking first whether its convenient. More than once a week is too much. Its causing you stress because you've tried to say this in person many times.
it is still a pandemic you have a young baby and whilst people might not agree, you ask them to respect your wishes about social distancing mask wearing etc. Its kind of them to give you gifts but the biggest gift you could have is some time and space to get used to being a new mother and to catch up with work.

sign it from both of you. Let them kick off but you know you are right, what you are asking for is reasonable and they are taking advantage.

They really want to look after the baby without me but I'm having a really hard time trusting them because they weren't there when we needed them and they keep doing things when I ask them not to

If they keep ignoring your requests they don't get to babysit without you. And you decide when and if you are ready for that to happen.

Either that or Your DH needs to firmly ask that they back off, start listening to both of you and give you some space!! Good luck.