Good start - for inspiration, you can check out Drew DeVault's (https://drewdevault.com) "bunnix", a Unix-like OS implemented in his own "Hare" language in about two weeks:

https://git.sr.ht/~sircmpwn/bunnix

Some suggestions for further projects:

* multi-core support

* portability, e.g. to an ARM or RISC-V machine (assuming you started on x86)

* networking