Automate as much as possible. I rsync to both an online and home NAS for all of my hosted stuff, both at home and in the cloud. Updates for the OS and low level libraries are automated. The other updates are generally manual, that allows me to set aside time for fixing problems that updates might cause while still getting most of the critical security updates. And my update schedules are generally during the day, so that if something doesn't restart properly, I can fix it.

Also, whenever possible I assume a fair amount of time for updates, far beyond what it should actually take. That way I won't be rushed to fix the problem and end up having to revert to a backup and find time later to redo it. Then most of the time I have extra time for analyzing stats to see if I can improve performance or save money with optimizations.

I've never had a remote provider just suddenly vanish though I use fairly well known hosts. And as for local hardware, I just have to do without until I can buy a replacement. Or if it's going to be some time, I do have old hardware that I could set up as a makeshift, temporary replacement like old desktop computers and some hardware that I use for experimenting like my Le Potato that isn't powerful enough for much, but ok for the short term.

And finally I've been moving to more container-based setups that are easier to get up and running again. I've been experimenting with Nomad, Docker Swarm, K3s, etc., along with Traefik and some other reverse proxies so o can keep the workers air-gapped for security.