Camera

I am litter confused that 7sII and 7SIII are old cameras with 12 mp, compared with 2019 lets say Alpha 6100 that is 24mp. Also Alpha 6100 have smaller pixel patch compared to that one. Although I dont get it why is pixel patch important for camera, wasnt that more important for display? I was looking 20+ mp camera and better shutter, because of moving object (drone shots). Also renting is not an option, I want my own, have multiple problems with renting.