Hi! I have Airpods Pro A2084. The volume function on it doesnt work. Is the volume not included on this model?

Hi! It looks like you currently have the first generation AirPods (via Identify your AirPods - Apple Support). From your description, I gather that you are not able to control the volume by sliding your finger up and down the AirPods stem. this is a feature exclusive to the second generation AirPods Pro, and their model is: A2931, A2699, A2698.

I have air pods pro

do you need to have your iPhone with you say at the gym to hear music? Siri helps me with sound but in the above question if I don’t have iPhone the side device does not adjust sound. I can stop and restart music.