Seems like its completely different person with the same name of Rafal Kupiec. Pretty common Polish name and surname. WinuxOS is not related to ExectOS by any means. The post is from almost 20 years ago.
Also I don't see that level of code similarity you're claiming. KeLowerRunLevel in Minoca is literally a one liner. Most functions behave differently compared to Minoca's. I've asked Belliash on Discord, he was reading Minoca to derive some inspiration. And Codeium AI autocomplete may sometimes generate code similar to other projects. Nothing to worry about.
It goes beyond one-liners. This is especially apparent in sysres.c, where not only are the function names identical, they appear in the same order. There's also non-trivial functions, that are obviously copied line-by-line, with some modifications. See KepGetSystemResource for example.
