What folders are important to sync if same nextcloud instance is running on 2 sites

I have nextcloud at 2 locations running and I am syncing entire data folder between both location and master-to-master replication of mysql database.

to minimize the sync I want to know what folders are requried to be synced ?

what is this folder under data/ appdata_ocr2fw9pzn5a ? does it needs to be synced ?

does the entire /var/www/html/nextcloud folder needs to be synced ?