Mine doesn't change gear perfectly but things like that don't bother me any more . I find as I get older my ability to do anything fiddly is aggravating. Between the natural age loss of eyesight and my cachhandedness I need a perfect nice bright day to do any simple maintenance . Chopping wood is therapeutic as long as you don't hit the fingers.Hmmm, I generally wear through 1 cassettes a year (1.5 maybe ?). Shimano XT 12 speed, HG Shimano chain, AXS GX. Chain checker says very little wear. Chainring is in very good condition.
My distance is down by 25% , probably because of some trail work this year. Now that I think of it, I’m down to 2 chains a year. But my chain is skipping/jumping in 4-5-6-7 gear while applying high torque. I’ve inspected every tooth on the cassette but I’m not exactly sure if there’s excessive wear on the shape of these teeth. I don’t know?
Maybe a thorough cleaning and/or disassembly of the chain, derailer and cassette may be necessary. A while ago I also changed to a different chain lubricant. Suppose to be better and last longer.
Bent or frozen link? Bent tooth? Dirty derailer?