I think that the idea that you might have to swap to Controller when "development becomes more serious" is silly. Controllers aren´t inherently more serious or clean. They prescribe you an architecture. Minimal API gives you much more freedom. For example it is much easier to swap out a few routes depending on deployments. Whats more clean depends on how you use either.

For the most part people using Controllers also throw together a lot of methods that somehow loosely connect to some arbitrary word. Sometimes the word is HomeController. What's "Home" supposed to be? Well... just about anything on this "Home" page that just so happens to have 15 sub menus. Seen this a lot.

There is absolutely no issue mixing controllers and minimal API. In fact you probably do it already if you use controllers without knowing it. As a lot of stuff like 3rd party login, or openapi docs will use minimal API under the hood. You just did not write the minimal API part yourself.