At this point, you can either accept getting that latest backup from iCloud or not restore the backup at all. Your iCloud-related apps data (Calendar, Contacts, etc.) should still be available from the iCloud Drive.
The issue is why iCloud only had backups of your phone since 2018, and that could be for a number of reasons:
- You do not have enough storage space on your iCloud Drive.
- Your phone was not configured to backup to iCloud at some point back in 2018.
- Your phone was not connected to a Wi-Fi network at the time a backup was to be preformed.
- Your phone was not connected to a power source.
See if any of the following support articles can help: