

Individual AppImages still highly depend on system libraries, I’ve seen them often fail to run on older distros, for example due to an out of date system glibc.
Flatpak is not owned by RedHat or systemd. You can use flatpak while avoiding systemd components.

This is an absolutely bottom of the barrel machine nowadays. You’ll be able to run Linux on it, but nothing is going to run “fast”. Especially not a webbrowser with modern websites.
If you’re actually considering using this machine, the two most important upgrades you can make are SSD instead of HDD, and a bit more RAM (8GB if possible). With the ~2011-2012 CPU (judging by the release date of the iGPU listed) and the mentioned upgrades, you should have a usable (although slow) workstation for light tasks. Without the upgrades, be prepared to wait for things to load.