Garmin Basecamp on Mac M1

My Oregon 600 has died so I was planning to buy a new Garmin Montana 700i or 750. However I've just installed the latest available version of Basecamp on my M1 Mac to find that it doesn't work. The base global map doesn't render proper, it's crazily slow, and it doesn't recognise anything from SD card. 

It's possible this isn't to do with the M1 Mac at all, but Basecamp's problems with Big Sur, which Intel Mac users are also experiencing. That being said it would Mac sense to develop a version that could run natively on the M1. 

I would love to buy a new Garmin GPS, but without a version of Basecamp that actually runs on an M1 Mac I might have to look elsewhere. 

I wonder if Garmin has any plans to fix this.