it could be the PC itself then.I’ve had this problem across two XB1 controllers and my new XSX controller even after clean reinstalls.
Its unlikely you get same problem on 3 devices, so if PC is one thing not changing in the switches, I would look at it. One way to check would be to see if problem happens on other PC with the controllers.
I haven't had any problems connecting to BT apart from the first time when I didn't know where the pair button was on controller - I hadn't looked in instructions.
i haven't noticed any latency on it yet but might pick up the Xbox Wireless dongle anyway.