I have been at university for about 3 years now, and I have not made a single friend because all the people there are too-optimistic-for-their-own-good capitalists, who think that they can make their own small business within 2 years of graduation. And they are Liberals or Republicans.
NGL this sounds like you are acting in an exceptionally abrasive manner. Online is never a full replacement for having an IRL community you can do things with.
0.000% of Communism has been built. Evil child-murdering billionaires still rule the world with a shit-eating grin. All he has managed to do is make himself sad. He is starting to suspect Kras Mazov fucked him over personally with his socio-economic theory. It has, however, made him into a very, very smart boy with something like a university degree in Truth. Instead of building Communism, he now builds a precise model of this grotesque, duplicitous world.
I won't pretend to have a panacea for unlearning the pattern that led you to be completely alone, but joining uni clubs based on common interests are a cheat code for establishing a social network. You are not the One True Communist here to spread the light of True Socialism to the masses. In the best case you are a water molecule out of hundreds of thousands that breach a dam. Take yourself less seriously and fake a smile. Odds are there's at least one person on campus who already thinks you're really cute.
With that out of the way now that I have said what stood out to me in ur post, here is a short description of each of my twenty fave comms.
/c/doomer - dedicated space for posting about anguish about the state of ting
/c/drugs - harm reduction and shitposting
/c/news - analysis community for the first draft of history. Hasbara banned on sight.
/c/chapotraphouse - general shitpost
/c/main - general shitposting but with arbitrary modding as part of the bit
/c/games - safe space for lowercase g gamers
/c/the_dredge_tank - for shitting on reactionaries
/c/neurodiverse - neurodivergence comm
/c/badposting - anything goes shitposting where even the absolute worst bits get five upbears
/c/the_dunk_tank - for shitting on high profile reactionaries
/c/science - from your username you prolly have some unique insight to offer here
/c/technology - tech news and support
/c/libre - linux and general FLOSS comm
/c/urbanism - car bad train gud
/c/cars - in america, you are executed if you try to ride a bike
/c/sino - CHYNUH
/c/soviet - DAVAI!
/c/history - generalized history community
/c/menby - mens liberation
/c/em_poc - anti- crackkker aktion
Edited because I forgot about evil reddit spacing