Windows OS in-place upgrade❓

OS : windows 2012
plesk : onyx 17.8.11

I would like to do in-place update of windows 2012 to windows 2019.

Or it is better to upgrade plesk 17 to 18 and then do upgrade of windows OS?

I have read this KB Is it possible to upgrade OS on the Plesk server?

But I'm not sure if I can upgrade windows OS.