VENI MASEESlim Men's Compression Shirt to Hide Gynecomastia Moobs Chest Slimming Body Shaper Undershirt

The chart suggests i go for a xl but the size guide suggests l based on measurements. which should i pay more attention to?

If I wear under a shirt will the shirt cling to it?

Are the seams visible through a tshirt? I purchased one of these before and it looks like you are wearing a bra through your tshirt

Do you order normal size or go a size smaller ?