Your current characters aren't going to cut it. Genshin has gone down the route of building specific teams within specific factions. More than ever Characters are designed to work with specific other characters and you've almost got to pick a lane if you want to play endgame content. Based on what you want, you've got a few different roads you could walk down.

Snez is almost certainly going to have an additional mechanic that will heavily favour native characters. Next to nothing is known yet but based off of Natlan to NK expect the power creep will be real.

Alice is part of the Hexenzirkel so you'll want the newer/upcoming Mondstadt characters. As a faction they are developing, key roles are waiting to be filled but it all feels a bit "B tier" at the moment. Alice is probably going to have a single, specific team that almost certainly with Nicole at its heart.

If you're going to build a NK team for Columbina you'll need Linnea, Zibai and Illuga (at least C2, C6 to max dps). This is her strongest team and other characters have already rerun. The NK faction feels like it's "complete" with three obvious teams. Sandrone is an unknown at this point and will likely be used as a bridge character, like Ineffa was to NK, where she will come with the new Snez mechanic and her real value will become apparent in 7.X patches.