I now have good notes for restarting new instances when we need to migrate for updated system software
The only thing I haven't done successfully (because of the multisite excursion) is All-in-One export/import
Think I'd like to be comfortable with that before I generate too much content
Maybe "practice" on my simple first website after restoration
Suggestions here welcome
My career was in technology but definitely not server/internet/website administration
Hopefully I've stumbled onto the best setup for me and know enough to maintain it now
Thanks for putting up with my slow learning curve !