I agree, X86 is too complex with its legacy hardware and obscure instructions and environments. It might not be a good starting place to develope hobby projects.
It's also by far the best documented and most consistent hardware out there, especially when it comes to configurations. Yes, it's grotty -- but at least you can figure out where the gunk is.
The OS is running in a customised RISV hardware in MIPS for educational purposes, you can read more here https://dl.acm.org/doi/pdf/10.1145/1275462.1275470 The simulator https://github.com/halfer53/rexsimulator
The BIOS has already been written for the serial ports, etc. So it is quite easy for me to interact with the devices in the OS.