Every now and again I try to make whacky builds just to see if they might work. This is one of such builds!
Grim Tools: Shieldbreaker, Level 100 (GD 1.1.9.7) - Grim Dawn Build Calculator
Enter - Fist of the Dragon, the flame damage unarmed ‘martial artist’.
Here’s a vid of the build doing surprisingly well. I’m sure with tweaks and a bit of more disciplined piloting, this build would be able to comfortably do SR 65, but but SR 75 might be a stretch
Enjoy.