Signs/hints that your hybrid battery was on its last legs

NiMH electrolyte has a problem with crystallizing as it ages, which means it can store less electrons, as low as 50% of orginal capacity before car gives warning lights. It's easily eliminated by deep cycling the pack several times. Back in the 90's laptops used to run on NiMH and had this problem. Lithium batteries chemistry resolved it for the most part, but if you have a really old lithium battery for your laptop it can charge and discharge quickly too.

 

You don't know how to use a phone app? But you used to run sound boards at concerts and used to be an electrician? It seems pretty clear that your avoidance of learning to figure stuff out is a problem, not your actual skill level.