https://docs.nextcloud.com/server/20/admin_manual/installation/source_installation.html
Google Photos exodus.
Smugmug is covering ~end of 2021, will think about this later.
https://help.backblaze.com/hc/en-us/articles/360047277954-How-do-I-use-NextCloud-with-B2-Cloud-Storage
https://cloudcone.com/docs/article/how-to-install-nextcloud-on-debian-10/
https://nextcloud.revi.xyz ㅋㅋ;