LEM, you may be surprised to learn that you did the RIGHT things according to the research. If you are a mum prone to depression- then having other loving adults care for the child a lot, such as grandparents, and having work outside of the home is associated with better outcomes for you and the child.
Realistically- how would it have been better if you had been sat at home, not doing your qualifications, becoming more depressed and frustrated. I don't see that as a better environment for your dd- what you did was sensible.
My husband was brought up a lot by his grandparents and it worked out very well.
There's no 'magic' way to live a life, and if you parent like that, you get a child without mental health difficulties. My mum was and is a fantastic parent, she has one child with mental health difficulties their whole life, one without. I call that luck in my case, and bad luck in his. Yes, there are things that can influence that, but it isn't as simple as being a great mum and that just transforms everything. There are lots of brilliant, great loving mums out there who did everything for their children, as well as lots who were 'good enough' and children still have mental health difficulties. Life is hard and these things are common.
Your daugher is an adult now, like yo. She's 27, not 17, and so she, like you, has to find her own way to live in the world. You can't make her happy, all you can do is find some way to rub along together right now which doesn't involve you getting too hurt or rushing around cleaning her house in the hopes it changes anything- I guess it won't.
If you feel like grumpy mum, and I really am one, in my pre-menopausal state, then change that because it's not nice to be grumpy! Exercise, the new 10 min brisk walk app might be good, I hate exercise, but even I can see moving my big butt a few times a week walking to work or dancing round the living room keeps me mentally and physically in a better state.
It's also important to know that your second daughter and you have a completely different relationship- don't pressure it. She's not there to be the perfect daughter second time round because you 'messed up', Your first daughter is just her, that's her path, it isn't what you would have chosen but to some extent you didn't control it. Who knows what her destiny is on this planet? She may have a lot of valuable contributions to make to her own small circle of acquaintances/relationships beyond what we can see right now. Your second daughter is a person in her own right- just be with her, listen, and steady the ship a bit within yourself. That will help most.
Everyone saying deal with your own self first is right, I'm afraid. Annoying, isn't it!