I run 2 old Juki pick and place machines. They run DOS 6.22 on a 486 I think. My biggest pain points are, 1) booting them up without errors, and 2) transferring files to them wirelessly without any floppies. (without installing any DOS software)

Closest I got was with a GOTEK and an ESP32 emulating a USB. But it was flaky so I dropped it for now.