I'm on my laptop so I thought I would elaborate on my first comment to give you things to watch out for if/when you update. I've been hosting mine with the zip file manually installed with my own Apache/PHP/MySQL/MariaDB setup for ages now without issue. It's been rock solid except for, like I said, the occasional changes required to take advantage of new features such as adding new indices to the database or installing an additional php addon. Here's the things that I noticed with updating to 28.

• The 3 dot/ellipses menu was missing in the web interface and was replaced with dedicated buttons for "Download", "Add to Favorites" and "Delete". Shift clicking was also broken. This meant that when I, for example, take a lot of photos for a holiday, I can't use the web interface to select a large range of multiple files and then move them all from "InstantUpload" into a more permanent album. I either had to use the mobile app, or do them one at a time. The ellipses menu, along with the options to bulk "move/copy" have been added back since then with the *.1 update, but shift clicking in the web interface to select a range of files is still broken.
• The "Retention" app, which is listed as a "Featured" app doesn't function any more. I used it to automatically delete backups of my Signal messenger, files in the "InstantUpload" folder that were over a year old, etc. You can enable it, but it doesn't actually work and just throws errors in the log file, which is now reported in the "Overview" portion of the "Administration" page with a note of "X number of errors since somedate", and prevents you getting the green checkmark. It's probably safe to assume that other apps will also have issues because I had half a dozen get automatically disabled with the update.
• Occasionally when I use the web interface to move or copy a file, I'll get an error message that the operation failed. Sometimes this is true, sometimes it's not and the operation actually succeeded. If it ends up being true and the move did actually fail, doing it again results in a successful move.

It seems like they've made some substantial under-the-hood changes to the user interface that shouldn't have been shipped to the "stable" channel. It's not completely broken, it "is" usable, especially after they restored my bulk move/copy button, but I still can't use the Retention app, at least last time I looked, so I've literally got daily cron scripts to check those folders for old files and delete them, then trigger an occ files:scan of the affected directories to keep the Nextcloud database in sync with the changes. This however, bypasses the built-in trash bin so I can't recover the files in the event of an issue. I actually considered rolling back to 27 for a bit, but decided against it, so if I were you, I would stick with 27 for a while and keep an ear to the ground regarding any issues people are having that are or aren't getting fixed in 28.