By the way, I noticed that text in the game has those boxes around it. I struggled to find the solution for some time and only recently found out how to fix it.
TLDR: When you convert a font for TextMeshPro you need to keep SP/PD ratio (Sampling Point Size to Padding ratio) at about 10%.
Here's a link to the post that helped me at Unity Forums:
https://discussions.unity.com/t/text-mesh-pro-box-around-text-unwanted-effect-bu...