Shortcut key to swap to main display

Hi, so I have two VP3268-4K monitors I use with my M1 2020 64GB MacBook Pro. They work a charm. When I switch them on, the main screen is randomly assigned, which means that very often I have to head to display tab in the preferences to choose the main one.

Anyone know of a keyboard shortcut to do this? Or some third party software that might be able to create one?

Cheers.

B