I think a lot of 'nightmare' MILs never actively set out to be that way. But, they genuinely cannot see two sides to a story. It's their view or... their view.
OP seems to be coming across like this. 'No means yes'- no. No means no. She isn't looking at another point of view.
Ie: "mil keeps offering to do ironing which I'd rather she didn't because it's a bit invasive and I can do it myself but she always does it anyway... I don't want to start an argument with myself and partner so I'll just be polite even though it bothers me".
Nice people tend to let others walk over them for an easy life. It still doesn't mean they don't like what's going on, though. Just because you think you know best, doesn't mean you do. I don't think you want to even think about there being another POV in this situation, because it would mean you'd have to actually address and change your own behaviour. You're more than happy with assuring yourself you're doing the right thing... only because it suits you.
And be real, OP, you 'need' to be on the go all the time? Well that's a lie if I ever heard one. You know social etiquette and rules. When you're in a restaurant waiting for a meal, are you in the kitchen helping the chefs? No. You're sitting at the table waiting. When you're on a plane, are you helping the air hostesses dish out food? No, you're waiting for yours. You can go to your son's house and not mother him (because this is what this is). He's an adult. With a partner. He's moved out. He has his own home. His own way of doing things with his partner. For God's sake, just go over and chat and stop going into mummy mode. Offer to make a cup of tea for everyone and leave it at that.
He clearly is a mummy's boy, but you need to quickly accept that if he's going to be a decent partner/husband to your DIL, you are going to come after her and any kids they have. That's exactly the way it should be, as well. He needs to do his own thing with his new family. Give him space to do so. You don't need to be in on everything. Every event. Everything her mum is involved in. Your DIL (unless she has a challenging/estranged relationship with her mother) will always put her first over you. So lose that expectation now.
And please, if they have any kids then do not move yourself in and "help" because no means yes and your son is "sooooo grateful". They'll ask if they need help. And by ask, I mean "I'm sorry to ask but are you free any days this week to see baby X? I'd really appreciate a helping hand". Not "hi mil, no I think we'd prefer just time ourselves this week to get into a routine".
If you're as genuine and nice as you're making out, you'll have no issue in stepping back and being a good MIL. If you won't, well... don't be shocked for a fall out down the line.