Update. I posted the above 35 minutes ago.
After making 4 distinct backups of the current database, I followed the steps which I outlined above.
It worked!!
I had made changes to an ACF field which for some reason did not take; code errored using the new field name, but worked great using the old field name which I definitely changed and checked and rechecked several times. This led me to believe it is a BAD idea to ever CHANGE an ACF field name!
After restoring, I verified that changes made to a test post were definitely rolled back. The database I have now is the database I had from three days ago.
Nevertheless, I would still appreciate any corrections or recommendations from real support as to the validity and completeness of the above steps just outlined.
Thank you!!!