Like many of you, I gave up on VMU's long ago. Popping two new CR2032 batteries into them resulted in *maybe* a few days before they were dead.
However, I just realized they make rechargeable CR2032 batteries (LIR2032). I'm kinda wondering if these are what were originally in the VMU's when new? It would make sense to charge them while playing the console, then have a day or two of charge before needing to be plugged back in.
Anyway, I have some of these coming... going to see if they work.
https://www.amazon.com/dp/B08LCT9KG9