OpenWRT saves settings. It’s what’s in the backup, and that’s what allows the router to return to operation after a power cycle.
Things get can sideways when settings are persisted across updates. There is an option to persist settings, but there are fewer headaches when settings are wiped and restored from backup.
This gets even worse when packages are in play. Packages aren’t reinstalled when the backup is restored, so any packages need to be tracked then reinstalled after an update.
You’re opting to self-manage the router by installing OpenWRT. You are the QA department, and it’s up to you to make sure everything works and any manual changes are made.
In a production setting, no not at all. Updates need to be QA’d before being released, especially network equipment updates, to prevent outages.
The Turris Omnia is OpenWRT based and does auto updates, but the Turris is also $300-$400 dollars.