I had an issue with the original Apple Magic Mouse that would not work correctly with NiMH batteries but work fine with disposable AA. The mouse would be fine for a few days then randomly stop working; using fresh NiMH would revive it again. I assumed it was due to 1.2v vs 1.5v but perhaps that particular mouse (or all Magic Mice) was just bad.
Looking at the discharge curve for an alkaline, much of the energy is below 1.2V even under light load. A device that works with alkaline and not NiMH due to voltage is broken as designed.
https://lygte-info.dk/review/batteries2012/Duracell%20Ultra%...
I have an acurite 5in1 weather station running on eneloops/laddas. It whines about the batteries being low but runs for about a month in any conditions. I just rotate and recharge them at the start of the month.