As most of us with 2012R2 machines still in service are going through this right now since it goes End of Life in October 2023, I can give some pointers that have helped me.
Unless you absolutely need to use 2022 for a feature it only has, 2012R2 can be natively in-place upgraded to 2019 and works very well. From my testing, there isn't really a huge difference between 2019 and 2022.
The biggest thing you have to worry about when doing an in-place upgrade is the services running on the server.
A simple DNS/DHCP server? In-place upgrade it.
A print server? try an in-place upgrade but be wary of incompatible drivers for older printers.
The only time I've gotten into trouble is when I in-place upgrade a system that has some non-Microsoft legacy application. Even then, most have worked without issue and just took some testing/validating.
The other things to keep in mind (if possible):
- If you are using virtualization that allows machine snapshots, snapshot the machine before attempting an in-place upgrade of the OS. If it goes badly, in many cases you can simply roll back to the snapshot and re-approach
- Have good backups. You should always have a good back up of anything you plan to upgrade or just in general.
If you get too far along and need 2022, simply in-place upgrade in step. You can update 2012R2 to 2016/2019 and then immediately step it up to 2022. 2016/2019 to 2022 in-place upgrades are supported.
