Nextcloud mobile app has integrated photo upload. Nextcloud server comes with built-in versions and recycle bin support.
if you are not an expert an look for an easy turnkey Nextcloud solution I would recommend Nextcloud AiO today. I you want more advanced but customizable solution based on the Docker community image look at docker-compose-setup-with-notify-push-2024
media
Photo app (and memories app as well) are pretty basic so it’s not a replacement of Google. You might want to look at something more comprehensive - Photoprism is often referred to be a good image management tool. Same applies for streaming requirement - there is no good integrated app - look at Jellifin, Kodi, Plex some run as Docker as well and provide DLNA support or Smart TV apps (not easy to implement with Docker).
backup
data on the client is not complete and you can not perform a real backup of you Nextcloud system from the client. you must backup your config, database and files if you want a complete solution. if your backup doesn’t include first two it doesn’t include versions, recycle bin, shares, calender, user rights, comments and meta data of your system. Dozens of threads exist on this forum describing different solutions and approaches check out backup backup-app. I would recommend following official backup/restore manuals and look at backup app which allows proper backups of the whole easily.