That would be a nice development.
I would imagine that the planned team would be an expansion franchise into the USL Championship, the level below Major League Soccer in our American soccer pseudo-pyramid. That level is in process of expansion, adding a team in Des Moines, IA in 2024.
You can see the list of current USL Championship teams in the following link, which are hosted by cities of similar size to Milwaukee:
https://www.uslchampionship.com/league-teams
A couple other online articles suggest the same:
https://urbanmilwaukee.com/2022/05/20/eyes-on-milwaukee-soccer-stadium-concert-venue-planned-for-downtown/
https://soccerstadiumdigest.com/2022/05/new-milwaukee-soccer-stadium-pitched-as-part-of-entertainment-complex/