I had the same problem. I was fed up with my Amazfit GTS 3 and pairing a Mi band 6 wasn’t possible when I tried. For now it made me turn back to my trusty Pebble Time Steel (left wrist) and an oldish Mi band 3 (right wrist) which I intended to put on eBay but fortunately never did. Gadgetbridge is connected to both simultaneously. With the Pebble I can even mark tasks (in LoopHabit) as done and have as many reminders as I want. The Mi is only there for pulse tracking. I’m happy with this combination but I can of course understand that not everybody would like this as one has to charge two devices. Edit: the Mi 3 was the last device without encrypted server side pairing if I remember that correct.