What I would try before completely dropping the Big Sur/Trinket combo, is use the Digispark way of loading sketches:Deprecation Warning: The Trinket bit-bang USB technique it uses doesn't work as well as it did in 2014, many modern computers won't work well. So while we still carry the Trinket so that people can maintain some older projects, we no longer recommend it. Please check out the Trinket M0. It has built-in USB, more capabilities, and is comparable in price!
https://digistump.com/wiki/digispark/tu ... connecting
Key to succes might be a cheap USB2 hub, not too fancy USB3 stuff.
And otherwise grab the best computer ever made: a Mac Mini 2009, they do like 30-40 bucks (cheaper than the dongle-chain you need for your BigSur machine), and run Catalina (last good MacOS), it is perfect for loading code on your boards and the ultimate back-up machine if modern tech lets you down.