It does bother me that Homebrew advocates using /usr/local, that is a choice that needs justification and I don't believe they offer anything convincing.

That said, you can configure homebrew to use any path (check the wiki), you just have to set other environment variables as needed (eg, PATH). For example I'm currently using /opt/homebrew.

(note: a large downside to this is that you have to compile everything and cannot take advantage of Homebrew's pre-compiled "bottles" for some packages)