I have an OG Model F (pre IBM XT, but the same standard) and used to have a Pro Micro-based Soarer's converter before it died on me.
I'm looking for a replacement that can be both wired (either USB, PS/2, or AT) and wireless (either Bluetooth or via dongle). Soarer-style macros would be a nice-to-have, especially for the missing F11, F12, and Meta keys.
I think building your own soarer's or tmk or qmk converter with a nice!nano and a battery should do the trick. I'd ask on the deskthority discord https://discord.gg/494h57Up