I triggered the rosetta install by duplicating terminal.app and doing a get info on the new one and checking "open using rosetta" per the instructions here:

https://www.notion.so/Run-x86-Apps-including-homebrew-in-the-Terminal-on-Apple-Silicon-8350b43d97de4ce690f283277e958602

one critical bug: after duplicating terminal, both icons had exactly the same name, no "Terminal (1)" or "Terminal copy": just two identical "Terminal" programs. Def a security issue there...