Advice on taking siege to the next level

I’m looking to go for a high diamond possibly even champ season next time around and at this point I’m well aware I’m gonna need a team but through all the lfgs and discord’s etc I’ve never found people who play the game as much or at decent times so I just end up between stacks or soloQ. I think my calls and mechanics are good enough to make it but anyone got any good places to find consistent stacks and also just anything that makes a champ/high diamond different from a high plat/low diamond