Wondering if it's feasible to turn pcgeos into portable code by auto translating most of its mostly-assembly code into C (and then doing cleanup passes both manually and using coccinelle). The "kernel parts" like memory management will require a rewrite, but that's simple enough.
The result might be small enough to run on esp32-level hardware: After all, it was originally designed to run well on 8MHz 8086 with 500KB or so of RAM present.