I just wanted to supply some or info relating to this bug UE-76825 which I’ve found in my testing.
The engine crashes due to a bug with the widget switcher in UMG, The engine doesn’t crash if I remove some of the widgets from the widget switcher in 4.21 then move the problem widget InventoryGUI over to the 4.22 version of the project but as soon as I add them back in 4.22 and reset and try to open an blueprint the engine crashes again.