im gonna make a double post to say this too:
if you're new to competitive tf2 and you think people dont play full time off-classes because they just hate fun or whatever, i encourage you to make a 6s team and devise a plan around playing with those offclasses full time. you will very quickly see the weaknesses of your class and realize that the 6v6 format is called "competitive TF2" for a reason. the other classes do not provide enough or are just straight up too bad to be useful with that player count. i also dont understand the obsession with off-classes being made viable in 6v6 because highlander is right there dude. you want to play full time sniper? wanna get backstabbed every 30 seconds? wanna play with 18 people in the server? its literally all right there for you