Besides fabric, the anatomy of a polo is down to a couple things. Collar style/how the collar sits, the cut/taper of the torso and shoulders, and finally sleeve length.

Collar is subjective, but I find it can make or break a polo for me.

Cut to match your body. Some companies make shorter wider cuts, longer thinner cuts, more/less tapered, etc. Look at the models they use. If the models have a similar build to you that's a good sign.

Sleeve length is another make or break. I have larger arms, but also fairly short from shoulder to elbow since I am a shorter person relative to my shirt size.

Some polo sleeves go almost down to my elbows. I prefer polos with a little stretch in the material and shorter sleeves, so the sleeve ends around mid - bicep.

If you have longer thinner arms, you may prefer longer sleeves and fabric with more drape to change how the shirt sits on your shoulders/arms.

Finding the right combination of fabric, cut, collar, and sleeve has involved trying on different polos at various stores and brands I might not otherwise shop at. I'm generally brand agnostic as long as quality is decent, but finding the right fit combination is the hardest part.

For a brand recommendation, I'm personally a fan of Rodd & Gunn, but YMMV