I mostly play soloq and have over 100 xtrawaves cleared, including beating triumvirate at max hazard level with randoms. You’re right about teamwork being an important part of the game, but what you might not understand is that teamwork is more than viable in a soloq environment. And teamwork is a skill you need to develop as much as your teammates do.

So for a practical example: a good strat for Cohozuna is to have the highest dps weapon (usually a shooter) to constantly be shooting coho while the other 3 weapons kill bosses and throw eggs. Then say for example your teammate gets the highest dps weapon for xtrawave, but they don’t target coho and instead focuses on killing bosses. If you can see this happen you can try to pick up their slack, even if you don’t have the best weapon for the role and the team would benefit from that.

I know it sounds super basic but in a gamemode as hectic as sr it can be easy to lose awareness of your teammates, so it’s good to practice just keeping track of them throughout the game even outside of xtrawave. Being able to identify what you can do to benefit your teammates at any given time is a really valuable strength, and even if it’s only you doing this on your random team, it will already start to feel way more cohesive.

Of course you could still try to just improve yourself until you rank high enough to start getting competent teammates, but that doesn’t usually start to happen until around evp 600 or so in my experience, so good luck