I have no experience with either CentOS or amazon’s offer.
Yes - unless you really know what you’re doing (and you wouldn’t be asking here if you did).
The standard way would be what @iwalker says: Upgrade the existing server first. (And in case you’re wondering, the versions of GitLab you need that aren’t available on Amazon Linux 2023, are probably older than Amazon Linux 2023).
You don’t say which version of CentOS you’re on, but I know that they have discontinued some of their offering, so it might not be easy to upgrade on that platform. In that case you’ll have to find a distribution that 15.2 was packaged for, migrate to that, upgrade GitLab (possibly just to 16.3, but as far as possible is the standard advise), upgrade the OS (or migrate to yet another distro), and upgrade GitLab the rest of the way. You might (but as said: I have no experience with it) get away with using an old version of Amazon Linux (I can see some existed before the 2023 version), but if you’re not set on Amazon Linux, I would probably go with one of the larger ones, it’s far easier to get help then.
