Have you considered MIDI rings like the Genki Wave or the Enhancia Neova?
One of the earliest was the “Hot Hand”, which turn up secondhand. I think I tried strapping one of those to a controller once though I can’t remember how successful it was.
The Glover software for the mi.mu gloves, now available separately, apparently has support for Micro:Bit which might be interesting to look at.
https://www.mimugloves.com/documentation/microbit/
Admittedly, none of these are especially cheap. I’m sure it would be possible to rig something up with a Teensy and an accelerometer as you suggest…