Me (22) GF(20) going through hard times (just a rant CC is welcome))

Sorry for bad english it isn't my first language

my lovely Girlfriend and i are now 10 months with eachother, this is the best relationship i've ever had. We talk everything we think about when we think we are feeling down etc, also instead of just going to other people to seek approval we just talk it out when we have an issue or a "fight".

We are both gamers, we like the same games, she plays on Xbox i on Pc.
She always goes silent or irritated when we game and other people heal me in games she always says she is bad a the game or fake, she doens't deserve to be good at the game, also says she isn't a good gamer and doesn't have a lot of online friend, she is always so angry when gaming and always talk bad about herself. which i normally talk down to with the saying "you're not bad, you're doing good" etc, she alwayys sayys she's playing bad when we toghether play games and always talks down on herself,

we both struggle with depression, we keep each other up,
i have acknoleged myself by loving myself and know my worth in this world even if i sometimes feel like i'm a waste of space

she also feels the same way of her but instead of saying she love herself and she' worth living, she just keeps telling me that she live because of me, and she doens't love herself. which worries me, i've talked to her about it that she needs to "stop" beign so dependent on me not like litterly but in a smooth way, she supports me i support her, but she keeps going into a downward spiral, she has Assisted living so she lives on a group with fellow people her age, there it isn't goign smoothly, she hates everyone there, her house mates keep making loud noises after the time you cna't make sound atc her guidence is also a asshole tbh, she also has a administrator so she can't just buy shit she wants, which also is holding her back , which is hard.

when i talk to her how i find it irritating that she keeps pushing herself into a corner that she is bad at games and just don't deserve love, and just keeps telling herself she is bad at everything, it sometimes makes me irritated whihc than i say to her but then when i say it, she beomes silent and says sorry to everything,

What am i suppose to do? i don't know it anymore
i want her to become a better person and grows, but it feels like she's just putting herself down and goign into a downward spiral