I’ve come to like Fast N Fitness: https://f-droid.org/packages/com.easyfitness/

For me when wearing an thin athletic shirt, it only shows along the trimming over the scapulas. Maybe with a patterned shirt it would be less prominent.

I don’t know this compares to the “traditional binder” you are refering to, or other binders you have tried, but I have found the “Becoming” binder from tomscout to be really great. The material is thin and can handle sweating without causing a problem. I find I don’t need to take too many breaks. The tightness is always a balance between flatness and breathing ability however.

Good to know!