The most common behavior is now what Steam Deck does and it defaults to neither in Desktop Mode.
windows has natural scrolling and tap to click / two finger tap to right click, and that’s the biggest market share
Yes, Windows has the biggest market share among Windows users. The biggest driver to get Plasma in the hands of users is currently Steam Deck and that throws both conventions out of the window and defaults to actual presses to click and circular movement to scroll down in Desktop Mode.