Thanks for posting this. Been using Linux exclusively for almost 10 years now but I still miss scrolling by clicking the MMB. I have some problems with my fingers so using the scroll wheel is rather unpleasant, yet necessarily, especially when scrolling down slowly and steadily for a long time (e g. while reading/scanning stuff)
I hate this “feature” but there is always a way to deactivate it in both the web version and the app: you can change the audio track on the settings of the video (e.g. behind the cog icon on mobile)