This is not a theme-specific issue (but a general WordPress issue) can you please ask here instead? Thanks! https://wordpress.org/support/forum/how-to-and-troubleshooting/
Ok – will do. I notice there is clearly something odd going on. Adding an item in Site Edit shows up on the site, but not when you look at the menu from dashboard – and vice versa.
I just tested this, and this is indeed theme-related… but only in the sense that this is a Block theme (not a classic theme), so this behaviour is to be expected.
In other words, it’s a feature (of FSE themes), not a bug.
To use any of the menus configured in APPEARANCE => MENU, you’ll need to choose to use the named menu under CLASSIC MENUS in the block editor.
On the other hand, a new menu you create in the block editor does not appear in the “classic menu” at APPEARANCE => MENUS…
… because the two are totally different.
In fact, some (most?) FSE themes do not even expose APPEARANCE => MENU at all.