You should do it. Easy to setup using either their official AIO image or the community-driven micro service one. I am using the latter and it's been amazing. It's completely replaced Google Drive, Calendar, and Contacts for me and with the DAVx5 Android App it feels like a drop-in replacement. I am also using the auto upload feature to back up my photos to it.
I would too, but after like a week I get bored of maintaining it myself when all the expenses summed together aren't much cheaper than Proton or likewise. This is what I was doing before submitting my independence to Proton.
Furthermore Nextcloud is just too damn sluggish. The web interface makes it seem like my server's idea of a CPU is a kid with a calculator and WebDAV isn't designed for cloud storage. I'll take new features being slow over my whole experience being even slower any day of the week.
I feel that. However, Proton's a non-starter for me as I'm using Linux, so no Proton drive client. Really scratching my head since Linux attracts the security conscious.
That's what I've done, using rclone bisync and my crontab. Like I said it works well enough, but far from perfect. Using a beta backend with an experimental operation, according to the rclone website, puts me slightly on-edge.
I did try Celeste, but stopped using it for two reasons:
I use Budgie, so Libadwaita apps look incredibly out-of-place. Inconsistency like that makes me physically uncomfortable.