If the hours you spend implementing and maintaining your DevOps exceed the hours of downtime you prevent, you're probably not making good use of your time. The less you build, the less you have to maintain.

I've been running a Python-based, highly custom web store solo since 2007, and it supports multiple people doing fulfillment. I host on Opalstack so as to outsourcing patching, email config, database maintainence, etc. I run directly in a Git repo (actually Hg, it's that old) and releases are "git pull && ./restart.sh". Rollbacks are "git checkout ...".

I've had to migrate/rebuild the VM about every 5 years. Tech changes enough in that time that no automation will still work unmodified. So I just keep good notes about what I did last time, and figure out what the new equivalents are when I finally have to do it again (updating the notes, of course). Database and Conda are easy to port. It's usually DNS and email integrations that are a pain.

As others have said, KISS is key. Industry DevOps is for a work setting with a decent-sized team, where you can afford the overhead of maintaining it all in order to make the overall team more efficient.