Cut but didn't publish this back in October, so I better hustle it up here before 2023 expires (in my timezone)...

The circular field is 21 mm diameter (smaller than a $0.25 coin) and the lettering around the upper arc is less than 1.4 mm "high" (typographically vs Z axis).

Rough cut with a 0.5 mm (0.020 in) end mill, then detailed with a 0.025 mm (0.010 in) mill.