I guess the title says it all. I did some digging around the archives and found a recommendation to erase entries 329 and 330 in the MENU resource (using ResFork) to get rid of the File and Edit menus but even after I erased those, menus are still there. [menubar] object is another lead but it only allows adding and/or customizing a few entries. My hope is to get rid of everything, ideally even the About entry (although that one is lower priority as one could always create a custom one using aforesaid [menubar] object).

how-to-hide-file-edit-window-and-help-menus-in-a-standalone

take a look at maxinterface.json (YourApp.app/Contents/support/interfaces/maxinterface.json). Just remove any menu entry you don't want to appear.

take a look at maxinterface.json (YourApp.app/Contents/support/interfaces/maxinterface.json).  Just remove any menu entry you don't want to appear.

How to hide File Edit Window and Help menus in a standalone