If you have an Intel Mac, another option is to update it with the OCLP app. This works with nearly all Intel Macs at least to update to macOS 12, which is all you need.
I don’t think it did. Database backups are normally obvious because after update there is a lengthy „please wait, we are updating your database…“ message.
At least for now, there is a temporary installer available to move back to the old version:
For Mac users who are not yet able to update to macOS 12 or later, we’re also making a pre-update installer available as a temporary option. This version will not receive future updates or security fixes, and may become incompatible with current Roon Remote or ARC versions over time. You can find the installer here.
Long-term, you will need to rely on the OCLP app or update the hardware to MacOS 12+.