I tried to use Centos long term, that was a disaster. Ubuntu and Fedora both broke a few times but I was able to recover them. However, Manjaro / Arch feels the most stable in my experience.
What was a disaster about it? I would expect pain crossing major versions, but you could plausibly have installed CentOS on a machine and just stayed there for 5-10 years with nothing more than the odd `yum update && reboot` and I would have thought it would be fine.
The uptime of the machine was great on Centos, but it came to a point I was afraid to reboot because of the package changes that could apply.
edit: I think some software I was using was EOL'd just for Centos maybe also prompting the switch.
Although certainly I can sympathize with the software eventually getting very long in the tooth, and jumping EL 7 to 9 could definitely be quite a change.