Here's a
Beta-specific keyed switch from Sicass Racing that might work for you. It states it's for 2018-2019 models and I don't know if 2021 wiring has changed in a way that would affect the plug-and-play use of this switch. I don't have any firsthand experience with it, but Sicass Racing products are generally known to be high quality.
Personally I think the fork lock provides greater protection though (assuming that you only opt for one or the other.) The fork lock locks the fork with the front wheel fully turned, so nobody will be able to simply ride or roll the bike away. Sure, with enough hands available the bike can be carried away, but that possibility applies to the key switch too.
I think the greatest risk would be if using the key switch as the sole theft deterrent. In this case the bike could be quickly, quietly, and easily rolled away without making any attempt to start the engine. Later the keyswitch could be easily bypassed by simply unplugging it an re-plugging in the original wiring.
Just my two cents...