Hi Peter,
So I would still recommend CentOS for one primary reason. There are two up-coming projects with a high probability of success to continue / replace CentOS 8, those are Alma Linux
https://www.almalinux.org/ & Rocky Linux.
Personally I have my hopes set for Alma linux, it is being produced by the same company we already deal with for a lot of products (CloudLinux, Imunify, KernelCare) so they have a vested interest in continuing to produce a product that feeds their infrastructure as well as having already produced several variants.
The 'swap' if you will to Alma Linux should be relatively straight forward, I would assume a repo swap to their repositories and perhaps a reboot after running updates from it. With Cent you also still have primary support for all of the typical software used in a hosting industry.
Now if this were a headless server without a control panel, or without needing any specialized software and you are comfortable with DYI command line work, Debian or Ubuntu either are not a bad choice. Make sure to use the LTS versions of each to give you the longest 'life' out of the OS.
If you've got any particular questions let me know and I'll do my best to help!
