MX4 finally got me looking elsewhere until I stumbled upon this: https://ergodriven.com/products/the-vertical-handshake-mouse

I got it specifically because they had a mini rant about the weight of switches that other vertical mice use, and while I couldn't tell if that was a real problem, that's the kind of mentality I used to ascribe to Logitech.

The MX4 is clearly marketing logic. The haptic feature adds nothing of note, and 100% feels like their marketing people got to preempt the core goal of making an ergonomic mouse so they could have a headline.