How can I see volume percentage on iPhone 13 mini?

Why can’t I see the volume displayed when adjusting volume on I phone 13 mini? I a am on the latest IOS 18. I use various sleep sounds (tracks) and each is recorded at a different level. I need to see what volume I have on my IPhone for each track.

[Re-Titled by Moderator]

Original Title: I want to see the volume percent displayed when adjusting volume