Perhaps you can also use
add-apt-repository ppa:nextcloud-devs/client
sudo apt-get update
sudo apt install nextcloud-client (nextcloud-desktop)
I think the official package for all linux users is the Appimage.
Flatpak and Snap are a little bit the windows way 
Years ago nobody needed the newest version of software and the distributor e.g. Debian patched the software and build the packages.