My MX Master 3 was great until the last feature you mentioned decided to enable itself and never disable again... Logitech calls it SmartShift and other people

My MX Master 3 was great until the last feature you mentioned decided to enable itself and never disable again... Logitech calls it SmartShift and other people have reported the same issue, SmartShift enables itself, and from that point onward no settings changes will disable it. It's pretty frustrating to say the least, the MX Master 3 was poised to fix the reliability issues the previous entries had otherwise (since replaced the physical scroll wheel click with an electromagnet in a very convincing way)