batch conversion to MP3 in MacOS 12.2 Monterey

Audacity version 3.1.3
Job: convert many .aiff files into mp3s in one go
Problem: documented method is to run ‘MP3 Conversion’ macro using ‘Files’. However, Audacity GUI insists one must save and close the current project first. Fine…done that. Eeek! GUI no longer shows the Tools menu so can’t get at the macro to run it.
(a) Open one music file or project file so GUI shows Tools menu.
(b) run ‘SelectAllRemove’ macro (see below) to close tracks but keep project window open.
(c) now run ‘MP3 Conversion’ macro using ‘Files’, everything works as documented.
Select All
Remove Tracks

If there is a better workaround for this, I’d love to know of it!

That doesn’t sound right.
What happens if you quit Audacity completely (note that macOS likes to keep applications open in the background, so you have to “Quit” audacity and not just close the Audacity window), then launch Audacity by clicking on the icon in the dock?