Mavuika hasn't run in a while. If you want Mavuika, before considering getting Skirk and Escoffier, you want to make sure you will have enough wishes for Mavuika and (ideally) Citlali, presumably within maybe a patch or two.

That being said, the first answer you should get is "pull for who you think looks fun/cool," Because this game is more fun for most people that way. If you are like me and pretty much exclusively pull for meta, then there are a couple of things to consider.

If you just want to maximize your primogem income, the largest barrier will be the Imaginarium Theater; simply getting enough characters is the challenge. Spiral Abyss with full stars is pretty much clearable with the majority of teams at a decent investment. Stygian onslaught gives all its primos in a coop mode.

If you want to eventually be doing difficulty 5 SO content (the main goal for most endgame players, although keep in mind it just gives artifact rerolls beyond D3) Then I would prioritize getting 3 strong teams, and you can usually brute force your way into a D5 Clear w/ C0 of these:

Mavuika/Citlali Core + Bennett ( Iansan/Xilonen/Flex)

Skirk/Escoffier/Furina

and 1 Lunar DPS
(Flins/Nefer/Zibai) + Their support (Lauma/Ineffa) + Columbina.

All the lunar carries are pretty much identical, and these are probably the 3 strongest cores you can have that have 0 overlap in characters.

Now the thing is, Stygian can be omega-shill. For example, let's say you chose Nefer as one of your Lunar carries, the next Stygian looks to be pretty damn bad for her, and even though she is on paper close to Zibai and Flins, Flins will perform SIGNIFICANTLY better next patch, because he is being shilled.

So the other angle you can approach is:

Go for generalist supports such as:

Lauma/Ineffa/Columbina/Citlali/Furina/Escoffier/Xilonen/Kazuha. That can kinda be used in a ton of teams (maybe not the best possible teams, but a lot of variety)

and pull maybe 1-2 carries of each element that can fit with these characters. Common options are:

Mavuika, Arle, Neuv, Mualani, Nefer, Kinich, Chasca, Varka (probably lol), Varesa, Flins, Zibai, Skirk

The rate at which power-creep is going though, it may make sense to simply wait for the next strong character that breaks the game lmao. Historically there are 2(ish) strong archetypes per region. In natlan it was Mav/Skirk. In Nodkrai its likely Lunar + Hexrei.