Plasma 6 changed the way scrollbars work for some reason. Now when you click somewhere with mouse1 the elevator jums there and the window content scrolls accordingly.
Previously, it would scroll by one window’s worth in the appropriate direction. If you wanted to jump to a given location, you just used mouse2 (typically the scroll wheel button nowadays). It has worked that way everywhere for literally decades.
After reading the very weird explanation for the change, I can only conclude that the devs don’t even know how to use their interface.
Hence my question, is there a setting somewhere to switch back to the traditional behaviour?
As with anything related to plasma, there is likely a setting for it when they change a default behaviour. :)
Indeed, that’s why I was so frustrated. Turns out I had just stupidly missed it. Shame on me.