I see physical self-improvement as a means to improve my self-esteem.

The part of this that reliably works isn't the mirror. It's capability.

Something shifts when you can carry all the shopping up two flights in one trip, or take the long way round without planning your day around it first. The body becomes something you use rather than something you assess. That's a different relationship, and it's the one that quietly changes how you feel about yourself.

Appearance goals tend to move as you approach them. Capability goals stay put and can be met. Pick something your body could do that it can't quite do yet — a distance, a weight, a flight of stairs. That's the version that pays out.