How do you achieve balance?

Sadly many people expect their families to do everything when there are many options of help available,l speak from experience more than willing to help including living in at points but ultimately family or even live in caregivers can no longer cope and they need to go into various care type facilities who can manage.

Another thing if they say it's very selfish of you say "I'm sorry you feel like that" but don't engage as they will pick holes in whatever you say by way of explanation

And of course, Minnie.

Completely agree with @doodleZ1.

Try to be strong OP, and gradually walk away bit by bit.
They will resist and argue - try to use this to your advantage - “don’t want to stay and argue, I’ll leave now and talk [at future time] when we’ve clearer heads.” Easier said than done but try.

CMOT and Doodle have put it very well.
You clearly shouldn't head down the path you are currently on and I guarantee everyone on this board will support you taking a different route
My piece of advice is switch from the back foot to the front foot ASAP.
Don't let her be the one barking instructions and getting you to work around her situation forcing you into too many family compromises and curtailing your career aspirations. Instead, take many steps back and become the person you want to be. Anticipate her needs and wants and have replies already worked out in your head for why you can't when she asks

I would prefer resentment on their part to my life being taken over when I moved them in, as well as the lives of my kids. You would be their carer, have no life no holidays no breaks and their health just gets worse not better. You know it's all talk. they can't MAKE you do anything. It's very selfish for them to do that to you. Did this person do that ie look after an elderly relative? Look at it another way would you think it was right to move in with one of your kids? I would rather die for that to happen to me and both my boys deserve a life not to be dragged down by me, that's not good parenting. Read all the threads on here it would frighten the life out of you and the advice given was don't do it don't take them in to live with you. Blame the kids blame your partner or just say no it wouldn't work but this is what I will do. Put it on repeat. They are being selfish taking your youth from you. Try and put up a mental forcefield and keep repeating you will organise help but have kids so they will have to get outside help. If there's a lot of moaning say you will have to go. Don't listen to it too long just leave. Best wishes

It's really hard! But you need to work out boundaries and also work out critical needs for care vs a desire for dependency (where actually they could do it themselves) I've experienced both.

I would if you haven't already get a full social services assessment, ask them for their expert recommendations for the kind of support they need and options available at what cost. Self funding obviously means less inheritance but I would suggest that it is better they spend the money on care than restrict your life!

Is there an option for warden controlled/extra care accommodation not too far from you? A compromise from living with you? If their needs are great then look into nhs continuing care which isn't means tested.

What age is the person you will be caring for? If you have young children I don't see that you can be there all the time it wouldnt work, while still being fair to them. Is it just you that is available? Perhaps seeing yourself as a facilitator and organiser and limiting your visits to what you are happy with and can do without resentment. Resentment will come otherwise. This job is full time and you can't do it on your own it needs outside agencies. Will they refuse outside help do you think?

I decided that my son (who was tiny when my parents first needed help) had to come first, then my relationship and my work. My parents wish to have me do things, rather than cleaners/carers/handyman/gardener/hospital transport etc etc had to come after all that in order for it to be a long term workable solution - and it was 15 years.
Of course I cared about my parents. But I wasn't going to sacrifice my life when by having strong boundaries I could keep them at home and safe while not having to do it all myself.
If they won't be self funding, take all the help social services will offer and only say you can do what will be do able in the very long term without your kids missing out. You only have to read the stories on here about the toll it can take on women who are guilted into doing more than one person ever can