Raspberry-Pi VS almalinux.org

I don't know x86, but I use ARM startup code called SmartStart by Leon de Boer that sets up everything for a Raspberry Pi before calling kernel_main (different models have different ARM CPU's and it handles the slight variations of each -- see SmartStart32.S for the 32 bit version and SmartStart64.S for 64).

For the Raspberry Pi I'd start with this "hello world" project . It gets you booted up, and control transferred to your OS in C starting at int main(). It provides printf functionality to the screen (and basic 2D graphics), access to many of the hardware registers, hardware timer and interrupts. Plus some global variables and functions relating to the system (made available in the .S startup loader).

https://almalinux.org (At the bottom, "Backed By")

This might be a good use case for RHEL family distribution (such as CentOS Stream or AlmaLinux) or Debian. These are much longer lived distributions, and provide fewer update churn over time than other distributions.

If If you feel more comfortable on a RHEL based distro, there a good alternatives to CentOS such as AlmaLinux or Rocky Linux.

This situation still exists and Gregory Kurtzer's RockyLinux (Greg started CentOS originally), CloudLinux's AlmaLinux, and others exist to fill the need for a freely installable RHEL clone.

If you go to https://almalinux.org and click download, then click "Get Live Media Image", you'll be sent to a page with that link as well.

Look at AlmaLinux also. I'm not sure of any technical reason why you'd chose one over the other, but AlmaLinux is a public non-profit with a board, Rocky ownership is a private org.

https://almalinux.org/

I moved everything to UbuntuLTS also, and I'm not moving again. But if I had waited, and I sort of wish I had, I'd probably be moving to Alma.

I was raised on Debian and I've been using it for all my Linux servers. On my ESXi I use VMware Photon OS as the host OS for my Docker. My primary client is using Alma Linux as the host OS for their Docker deployments.