Install as Flatpak
There is a community maintained Flatpak org.qownnotes.QOwnNotes on Flathub.
You can install it by typing:
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak install flathub org.qownnotes.QOwnNotes
Afterward you should be able to run QOwnNotes with the command flatpak run org.qownnotes.QOwnNotes.
Info
Please open issues with the Flatpak package on QOwnNotes Flatpak Issues.
Tips
If QOwnNotes logs Could not write secret to keychain, install the missing Secret Service packages on the host system and restart your desktop session.
For GNOME and other Secret Service based desktops, install gnome-keyring, libsecret and seahorse.
For KDE Plasma, install KWallet support such as kwalletmanager.
QOwnNotes will fall back to legacy encryption if the desktop keychain is unavailable.