GTFO is on a small decline if it comes to playerbase, but on their discord there is a lot of helpful people. Devs are working on matchmaking which lack of, turned off quite good number of players. It's not that much of a hustle, but you need to put some work to get 4P party.
I bought it and I don't regret it, but devs are quite slow with updates and communications. It's best to wait for a discount or their next patch - can't really say what will come sooner.
From the other hand, Deep Rock Galactic has bigger than GTFO community (slightly over 2x) and very active devs. Even though the game is a bit repetitive, it is fun, especially with friends. With randoms it's still good, especially when you get people focused on teamplay.
You can also try Dead by Daylight, the game is fine but it has extremly toxic community.