You seem very aware of the problems, in a really healthy way.
First, start to work on yourself. Make a list of what you are good at, paying special attention to what you love and what other people praise that you take for granted. If there is something that overlaps - you think it is easy and love it, other people think it's hard and admire you [ that is the sweet spot for earning good money and/or having a job with self respect. Doesn't matter what it is. Start applying for roles that need your key skills or consider setting up freelance or as a business that puts them to use.
If that feels too daunting, start with improving your social life. My recipe for this is do three things a week -one that keeps your body fit, one that keeps your mind healthy, one that connects you to the wider communiyt. So body could be a dance class, running club, bootcamp, netball club, yoga. Mind could be a meditation group, a church if you have faith, group therapy etc. Community could be helping at a foodbank or soup kitchen, with local gardening or litter project, in your DC's school in some capacity, at a local animal charity - whatever you like. But do those 3 things for at least a year to get you established in the world, to take your place in it.
If you need a job, any job, then take one with the aim of improving how you manage boundaries and respect. There are always jobs in care, for example, and they can be very rewarding but given the shortage of care workers, there's no need to tolerate being bullied, or always being the one put on crazy nightshifts etc. So you could take the job and practise setting healthy boundaries and looking for opportunities to develop your skills and training wiht a view to getting promoted.
Also, just practise having an opinion, independent of anyone else's - what are your opinions on politics, gender, education etc. Just think about them - why you believe what you do, where you diverge from DH's opinion, or your parents etc.
Are these the sort of things that help?