Basically as the title say., I've had the feature turned on for literal years at this point and just now when I went to a store page I got jumpscared by a video starting at full volume after I scrolled straight past to reviews (was checking on a game that I was interested in that came out recently hence scrolling all the way down right away)
Checkbox that'd normally be there is completely gone, restarted the client in case it was a bug and checked game pages that have youtube trailers as well as ones with videos hosted off youtube and literally all of them autoplayed regardlesss with my prior beloved no autoplay option totally absent </3

Even when I did manually play videos before I also had the volume on mute by default to manually adjust bc varying video volumes so stuff popping up in full volume is a whole other issue in itself tbh

ETA: Resolved, they changed the video player and that overwrote settings. Now rather than a convenient and visible box the option is under the cog wheel menu ugh.