https://macrofactorapp.com/body-composition/

Estimates in level of inaccuracy on the high end ranges from ~5% to ~10%

If you see your lean mass going up in DEXA, your muscles are getting larger, and you're getting stronger, particularly across a wide variety of exercises where CNS adaptation can't explain the strength gains, they're likely broadly accurate.

Mine have all tracked quite closely with what I'm seeing in the mirror and what is happening when it comes to the amount of weight I'm moving.