Understanding the technical architecture and managing and building teams as well as reviewing budgets and aligning to plans aren't two skill sets that are intertwined. It's very common to have one person great at one and another great at the second.
If it's made clear who is responsible for the architecture then it is clear who makes decisions there.
Likewise, that person can focus on the technical architecture and someone else is doing the people management, timelines, budgeting, and so forth.
What's the alternative? Promote the architecture person into a managerial role and have them be unable to scale the teams?
Or promote the other person, scale the teams, but run into technical issues and debt because there isn't a person owning the architecture and keeping the mental blueprint in their head how all of the pieces fit together?
It really comes down to getting the right people on board, clearly explaining the responsibilities, ensuring compensation is equal, and then having the two parties see each as allies on the same team.