I tried to use Nextcloud before, and I was disappointed with how it handles syncing large quantities of files such as photo galleries. I wouldn’t use it again for such tasks, at least the current release, but it can do much more than syncing pictures: it has a lot of official apps that are few clicks away, and I was particularly interested in “Contacts” and “Calendar” apps. That was exactly what I needed for a long time: a reliable alternative to Google services that can keep my Debian laptop and LineageOS smartphone in sync.