Yes, I'm sure, it exactly like that on this very machine where I type this comment. However, the Apple Silicon version installed into /opt/homebrew creates the

Yes, I'm sure, it exactly like that on this very machine where I type this comment. However, the Apple Silicon version installed into /opt/homebrew creates the repo directly in its prefix, just like yours installed into ~/brew. Here the content of Homebrew dir is mixed with Cellar, Frameworks and Caskroom, which are normally one directory up. So it looks like it behaves differently when the prefix is /usr/local.