C2 Columbina or C2 zibai?

I'm in a tough dilemma - unsure on whether I should get c2 columbina or c2 zibai.

I've been told that if I only plan to run columbina with zibai then I should get c2 zibai because it would be a bigger dps increase.

in my case, my columbina indeed is going to be only with zibai as I don't have any of the other lunar characters nor do I plan on getting them, my geo element is also severely lacking so I could use a geo dps.

the problem is that columbina is the main character I want, getting zibai is just so I can have a team with columbina, so on one hand columbina c2 is what I want, on the other hand I'd feel pretty dumb doing that knowing c2 zibai would make the team better than c2 columbina.

and the third concern is that there might be more lunar dps characters coming in the future that I might want to get, in that case columbina will be moved to that future team which would make c2 columbina better because it's more versatile with columbina able to be in different lunar teams.

so overall I'm really not sure what to do, unfortunately I can't afford both c2 bina and c2 zibai.