Is Seafile any good? It’s similar to nextcloud, but apparently faster etc.
https://play.google.com/store/apps/details?id=com.seafile.seadroid2&showAllReviews=true
https://apps.apple.com/cn/app/seafile-pro/id639202512?l=en&platform=iphone
Mobile apps both have pretty bad ratings on the app stores.
What would you host for yourself, friends and family, basic dropbox functionality is all I need.
I have hosted Nextcloud in the past but it’s a huge program with way too many tools, apps and a complicated way to update, the end result is often a slow and not very comfortable way to use the aforementioned basic dropbox functionality.
https://syncthing.net/downloads/ there’s an android app. But I think I have experimented with this a few years ago and it seemed to use a lot of battery.