This might not sound like a very nice way of dealing with it but sometimes, needs must...
I was brought up in an emotionally/physically abusive family. My brother was the Golden Child and suffered differently but I didn't see that at the time. He was also abusive towards me because my parents had convinced him that I was the problem. I had a good relationship with my grandma until my mother sabotaged that too with her lies. I have no other family.
I've been nc with mother for 11 years and also found myself in a loveless, sexless, emotionally and financially abusive marriage.
I put myself through university and got a first class degree and a masters in my 20s. I entered a profession but will never progress because a) the thought of it scares me (I have huge imposter syndrome) and b) after living with so much stress, I can't cope with it. It's taken years to be able to work full time. I'm now in my late 40s and this is 3rd year of working full time. That's an achievement for me.
I live in a nice, but small, house in a pretty crappy area. It's rented. My mother sabotaged my attempts/plans to buy a house (she deliberately gave me very bad advice and, by the time I realised she'd intentionally sabotaged that too it was too late for me financially).
She told me from being a young child that no one would ever be attracted to me, love me or want me because of... well reasons that were everything about me physically (body shape, hair colour, fingernail shape, ankle/wrist size, waist size, neck length, skin colour etc) and everything about my character and personality - too intelligent, too opinionated, too outspoken, too... everything else. But also not quiet, compliant, demure and everything else enough.
I was trained to be as mediocre, as middle of the road, as inoffensive as possible in the hope that some day someone would settle for me. Ultimately, she failed. That is an achievement on my part.
She spoke to my school to try and get them to reduce the number of GCSEs I did because I was a girl - want did I need qualifications for? And it might put a man off me if I got ideas above my station. School (fortunately) and I ignored her. That is an achievement.
I was a gifted musician but she sabotaged my plans to become a musician because a man wouldn't tolerate a wife in that industry. I didn't pursue a career in music but I have made it part of my job anyway and now play for pleasure in a gigging band. It took until I was 44 to do that but that is an achievement.
I resisted her attempts to teach me to cook because it didn't occur to me I'd need to feed myself one day, she only talked in terms of feeding my future hypothetical husband and entertaining his boss and the boss's wife. I had no intention of ever doing that. I taightyself as an adult and I'm a pretty decent cook now. That is an achievement.
I reached adulthood with no sense of who I was other than a failure in relation to men. Told I'd only ever live half a life without a husband but possessed none of the attributes required to find one.
And so it went on.
I've been homeless (at my mother's hands); I lived in a hostel with my newborn son. Nine of the staff understood why I was there. The other women were drug addicts, sex workers, women undergoing parenting assessments with the LA. I didn't have my child removed from me. In that environment, that was an achievement.
She tried to get SS involved with my son. Using the fact I lived in the hostel as the reason amd everyone else there had one. But everyone else had serious reasons for being there. My mum just wanted to perpetuate the narrative that I was a problem and she was my victim. I went to university upon leaving there. That was an achievement.
Anyway, I bumped into one of the women from there when I was in the final year of my degree (I was 29 then). She was still invovled with SS. Her boyfriend was in prison. She lived in a crappy flat where you could smell raw sewage in the bathroom. She didn't work. She'd had a 2 more children. She was on drugs. She'd been a really sweet girl who'd just had a shitty hand dealt in her early life and she'd never managed to get herself out of it.
And I took from that that at least I wasn't her living her life. And that was also an achievement.
There will always be people who have it easier and have better lives than you but there will always be someone who is worse off. That you have achieved what you have is your achievement.
Therapy will help but it isn't a magic wand. You have to see what you have overcome and the life you have built as valuable.
Everything you have. Everything you have done. Everything you have had to overcome in order to provide yourself with those things. That is your achievement.
Stop expecting external validation. Quite frankly, who gives a shit what anyone else thinks?