I solved it. ArcMenu is a system extension and is only partly Gnome 43-ready, so I disabled the extension.
The Left Superkey is in General Settings so it can still run independent of the ArcMenu system extension.
ArcMenu no longer appears on the top menu bar which was already too busy
So as this is a workaround to the thread’s title, l will close the thread and move onto the next exciting Gnome 43 bug.