After testing the megamenu for a while with different site modules inserted, it seems like its some modules that don't behave. I suspect this is partial because of the upgrade from Joomla 3 to 4 and then replacing the shape 5 template with the JA UBER template. I finally have the Solutions menu working the way I want after moving menu items from one Menu to a temp, then to a new Menu item, otherwise it would lock up as before.
I still think there is some conflicting JS or something similar based on what happens with changing settings in Megamenu, but I don't see any real errors with Browser Inspect. At present, I literally have to go out of Megamenu after any single change. Nothing updates while I am in it. If I click the save, then select another menu block for a change, no information updates. This appears to be the bigger problem and may be part of the reason for the lockups.