Spent two hours trying and failing to get Thonny to talk to Badger, then realised My Linux Mint 19 was using Thonny 2.1.16. Downloaded 4.0.0 from Thonny site and everything is fine. Might well be worth mentioning in the Guide??
Oof, yeah, that’s a pretty old version - I suspect it won’t have known about Pico/RP2040 devices. I’ll add a note to the tutorial about downloading the latest :)