First off interesting thoughts on him being pathetic in addition to his "self hate". My personal belief, and pun very much intended, is a crippling and very real lifelong case of narcicism.
Cosmo had a rough childhood. He was bullied relentlessly for his looks/teeth, and grew up in a poor household with at least 1 confirmed habitual drug using mentally ill parent (his mom). They live so far outside the normal spectrum he never even learns out to drive. They do, however, take out some student loans so he can go to an expensive private art school in Chicago. He stumbles upon something that he's really good at and has the time to do (speedrunning), gets popular at it and draws attention to it; too much attention, actually. Folks that are far more talented than Cosmo begin to easily overtake him and instead of either being happy with being an expert commentator type of streamer or putting in the added work to remain competitive, we get the self destructive/pity arc.
I say Cosmo invented the blind narcisism as a self coping mechanism a long, long, long time ago as an escape / way of dealing with the all to obvious reality that was his pathetic life. You can absolutely see the pathetic points before the estrogen; take a look at when that one dude commented on a mistake Cosmo made during a GDQ run. Cosmo lost it, went back to his hotel room and sicced his entire Twitter following to harass this dude relentlessly.
i think Cosmo hates himself in the sense that the drugs and over the top claims he makes are ways to distract himself from real life. In addition, though, I think he really does miss and crave the dopamine from attention, and at this point he cares more about the quantity/volume of attention than whether or not it is positive or negative. Lots of the shit he does is just to stoke the flames more on our side rather than cultivating any meaningful type of relationship with his followers. 99 times out of 100 if Cosmo is engaged by 1 of us he will immediately ignore a room full of paypig clingers and engage solely with us.
I believe him losing his own residence was crushing because, while he still tries to keep up these ridiculous claims, everyone (even his supporters) know the party is over. He's not the greatest and never was; he was an early adopter that refused to get going when the going got tough. I hope I am wrong but i don't see Break the Game ever being released and I don't see Cosmo ever coming back to any type of regular streaming because even he is realizing he is just another pathetic 32 year old man.