This. My system volume is calibrated to be similar across all applications, games, etc. This means all apps are individually adjusted to reach similar volume level. Why should I have to mess with all of my other volumes just random manager at Youtube decided a volume slider on shorts isn't necessary despite the site still using volume from regular videos where it can be adjusted? This isn't an issue with any other app or platform. Maybe the last Youtube video I watched had overly quiet or loud audio compared to the norm and I either have insanely loud audio or I can't hear a damned thing and I can't fix it quickly like on any other Youtube page.

Not everyone had a set of dedicated volume buttons, or wheel, etc. on their keyboard, so having to go into Windows settings or reach for a knob or button on the speakers themselves to adjust is a lot more than getting a slider like every other website in the world gives you.