When you access "Advanced Backups", is the option not there at all or is it greyed out?
No such option at all.
That option downloads (which means exports) a file with all your settings and metadata (labels) that you can save on your device. I don't see an import button. How do you import your labels from the same downloaded file or another BIP-329 compatible file?
This means import rather than export.
It may be used after wallet restoring from SEED you know and
any BIP-329 comparable file relevant to this SEED
labels are bound to addresses that in turn are bound to SEED. Just tap the relevant file: