Thanks for the kind words! I'll echo rajeevk's recommendation: the OSDev wiki is full of useful documentation and guides for setting up a bare-metal toolchain. There's also a community forum with a wealth of knowledge just waiting to be read.
In terms of boots on the ground, I remember once seeing a mantra from someone on the OSDev forums that went something like this: building an x86 OS is first about getting the CPU into a usable state, then about getting as far away from it as possible. This is really true! There's a lot of work to do to set up the features that any modern environment needs as a baseline: paging, segmentation, interrupt descriptors, etc, but once you're done with all that you're free to roam in the design space and build whatever you like, however you imagine, building abstractions and then abstractions on top of those.
I'd liken the early stages of OS development to a tech tree in a video game: you need serial output so that you can debug your kernel. You need to be able to allocate memory so that you can create pixel buffers, then need drawing primitives to fill them up. You need processes, and a scheduler to coordinate them. Every new feature you add opens up a myriad of possibilities that weren't there before, and although many things have a serial list of dependencies, there's always so much to do that you can just focus on whatever feels particularly inspiring to you at any given time. It's really a lot of fun.
axle also uses structured messages for making requests to the kernel, as well as everything else. Here's an example of some structured requests that can be sent to the kernel: https://github.com/codyd51/axle/blob/paging-demo/kernel/kern.... Here's some structured data that an application (in this case, the window manager) uses to interact with other apps: https://github.com/codyd51/axle/blob/paging-demo/rust_progra...
All the best, and feel free to reach out to me as well!