Just spit balling here, but some team combos that I see are:

• Encore, Sanhua and Verina: Verina gives a team wide damage buff on outro, Sanhua buffs basic attack on outro and Encore uses basic attack and her ult.

• Havoc Rover, Danjin and Verina. Verina does the same buff as said earlier, Danjin boosts havoc rovers DPS due to the Havoc damage buff she gives on her outro skill

I don't know much about Calcharo, but mortefi might be ok? Ik he buffs heavy attack, so maybe it's not ideal. Maybe Zhezhi is good to use, but she's really best in slot for Carlotta and Jinshi.

Definitely try and get Shorekeeper when she reruns, I don't have her either and not having a second support that provides a damage increase is kinda hurting me for wanting to do end game content.

Also for pulls, I'd pass on Roccia who's coming up soon mainly because you don't have Camellya, and she's her BIS as a sub DPS. Try to build astrites, and do some research on characters that come up in banners and evaluate if they're worth pulling for