That’s WoW in a nutshell. Either make friends, tank/heal, or run your own key. There really isn’t any other advice anyone could give (I guess you could buy runs, but I’d hate to think what a 15+ key would cost right now lol)
That said, giving Warrior a unique group ability (and the ability to help with affixes) probably wouldn’t be uncalled for. I’ll invite whoever so long as I don’t need something specific, but there’s really no reason to fill a DPS slot with a Warrior if an equally geared/IO Ret, Enh, Rogue, etc. is in LFG.