>Preferrably, I should be using an SSH key, but for the sake of simplicity in this article I am sticking with simple password authentication.

I prefer to see something that improves over current best practices.

I accidently had a setup like that. But it turned that wireguard had/have the ability to get stuck. Probably problem with the implementation from mikrotik.

A watchdog of some kind is needed for this kind of setup.