Unpopular opinion: Ultra lightweight mice and split button designs are overrated
Everything up to 85~g is perfectly fine and going to low hurts my ability to aim precisely. Personally I wish my O- was 8~10g heavier.
There are no massive benefits to have the buttons seperated from the shell but a lot of negatives like extreme wobble or flex (looking at you, MM710). Sure, seperated buttons can be very good and have very light clicks (looking at you, Logitech) but non-seperated buttons can be extremely good too if the shell isn't too thick. My now sold DM3 went from stiff to very light and crisp clicks after sanding down the shell (google zowie clicks mod).