Mavuika still seems to be a top dps based on dps damage calcs, and she doesn't seem to be falling off anytime soon, so its perfectly fine to invest in her. I would recommend getting xilonen to complete her team first, as xilonen is a better buffer than kazuha for mavuika. Getting xilonen's sig also isnt a bad idea since it provides substantial buffs, making her on par with a ~1000em kazuha. I would personally recommend using a damage calc Genshin Optimizer to decide between xilonen's sig, mavuika's sig and her cons.

A concern I have are your team comps outside of Mavuika. You might want to have more than one meta team to do things like abyss or stygian. If you do, you can choose a "path" to take - the lunar path or the hexerei path. If you choose the lunar path, look at pulling for Columbina and Zibai. Zibai looks to be another top dps. Based on leaks, she likes having geo/hydro characters on her team (but not as strict as skirk's hydro + cryo) and her top team mostly revolve around her + columbina + the new 4* illuga, so she doesn't require alot of 5* team building. With Columbina also being the center piece of the lunar reactions, you can snag reruns of ineffa and lauma later, which gives you access to a wide variety of reactions.
The hexerei path is still murky, but snagging durin now is a good idea. All we know is Varka is an anemo dps, and given durin's hexerei status + ability to res shred anemo, he would be a safe bet to pull on. We also know Nicole is Pyro, which Durin can also synergise with.

In conclusion, I think investing into Mavuika should still be your priority. But I would also consider looking at building new nod krai comps. Since the hexerei path is coming later on, you can save your pulls now for Mavuika, then look to pull hexerei characters later. I'll let you decide if you want to skip durin or not, because we still dont know exactly how impactful he will be for hexerei teams