my son and me, strange euss application

I married a polish woman in 2009 and came here (I'm from the USA). We have two kids, one biological. We separated after 3 years but never divorced. She wouldn't give me her tax records so when my residence card expired I couldn't get a new one. Legally I still retain the same rights but essentially lost british recognition of those rights. So for the last 8 years due to the hostile environment policy I've been unable to get a job, a bank account, rent a flat, go to the doctor, or re enter the country if I chose to leave. I know I could've made an application without the right evidence and appealed and it shouldve worked, but I found the prospect of making an immigration application I knew would fail to be daunting, especially as the main carer of two kids of an abusive person.

Most of this time, though I was the main carer for my kids, their mum got child benefit because I didn't feel I could take it from her, being unable to rent meant I had to raise my kids in friends' houses. About 3 years ago she was arrested for being possession/usage of cocaine and when a social worker got involved, my son told his school therapist his mum abused him, he's been with me ever since (our daughter is 20 and at uni). He sees his mum for an hour with me there every 3 months (this is his choice), otherwise I am looking after him. I've had child benefit since then.

So, I need to apply for settled status for us both and though my life has been difficult I've managed to raise two wonderful people, change is really scary, and so is the home office. His mum and sister have settled status. I am still her husband, but I don't have a residence card.

Before corona I did a thing where I applied for JSA (I had been here long enough to be permanently resident, but again didn't have british recognition of that), for which I needed to prove habitual residence, which I couldn't do without her tax records, so they declined me and I appealed for two years until I got to a judge who subpeonad the HMRC for her tax records which prove she has been exercising treaty rights this whole time, and I won, I have universal credit now and live in a hostel because if I try to get a job or rent a flat they will call the home office for an immigration check and the home office will hear I have no residence card and just tell them over the phone not to hire or rent to me, I know because it's happened to me multiple times, forced to leave jobs I was good at and flats I could have rented.

So I have, not her tax records, but a printout from the HMRC showing her income from work she filed for each year. It was enough to prove residence for JSA. I tried to apply online and they said my case was too complex. They sent me a 50 page form but it's for a chen case of a self suffiecient child. Which ok, maybe that is the only derivative right to reside form they have but I also can get it as the husband of an eu person, my wife has settled status, I just don't have the normal evidence one would use to show this.

I need help knowing how to apply, I can be a husband, or an Ibrahim / teixeira case? or can I apply as both? Should I use the chen form and add a cover letter explaining how my case is different, and that I qualify in multiple ways? They told me over the phone I needed to do my case first and then my sons, is that right? My son's going to secondary next year and they want proof now, I got a letter, so I'd like to make his application at the same time (I don't need to link them if thats the issue)

sincere thanks for any help!