What I always do is spin up a new vm and see that it works and then restore a backup there. There is no down time and no risk that something will go wrong and leave you stuck. You can even use a elastic ip (I somehow can’t remember what digital ocean calls it) and switch it over, so you don’t even have to change dns.
If I needed to keep the same physical machine, I’d probably move sites to a vm for a bit while I upgraded the machine with a clean install and then transfer over.
Otoh, I’ve seen plenty of reports of people doing its upgrades and it works just fine if you some mind the down time. But do make sure that you have a backup so you can spin up a new server should something go badly wrong.