[testosterone]

What's the best photo enhancement app to use today for men?

[fuckvolume]

you mean to smooth the skin etc...? that's a very feminine catfishy thing to do, I don't think it's a good idea
but for fixing colors and adding a bit more intensity you can use rawtherapee on computers or snapseed on android, that's what I use

you can work with shadows, highlights, white balance, vibrance... just don't make it obvious that the picture has been edited