Here's the catch though: how would someone work with people they know if they don't know anyone doing game projects? The only answer is to meet new people that are working on projects. In-person events can be awesome but they aren't accessible to everyone (especially when it comes to financial costs and safety concerns for marginalized peeps like myself). So that leaves online communities as the best option for a lot of people (even if the relationship building is slower to start).
For me, it's kinda been like this when I've been looking for portfolio-building projects lately. Step one, what projects I am finding sound interesting to me to work on? Step two, contact them with some stuff I've already made for them to listen to (I make music). There's always some nerves but I get better at contacting people the more I do it. Step three once I'm in contact with someone, is this person nice and do we get along? I'm not just looking for one-off projects (although those can still be valuable). I'm personally looking to build longer term working (and very friendly) relationships where I can do repeated work with people if possible.