Basic to intermediate difficulty - Only suitable for you if you feel comfortable:
At the time that I installed Linux, it took some troubleshooting to get the integration of Ubuntu's proprietary Snap packes working in KDE Plasma's Discover "app store."
In hindsight, I strongly prefer Flatpak, because it is not proprietary, provides better security, and is generally a bit more efficient. If you do need Ubuntu's Snap proprietary packages and have problems using it with the Discover store, the following could solve your problem.
1. Make sure plasma-discover-backend-snap is installed:
sudo apt install snapd plasma-discover-backend-snap2. Clear the Discover cache
rm -rf ~/.cache/discover3. Ensure the config directory exists:
mkdir -p ~/.config/discover4. Manually enable the Snap backend
echo "[Backends]" > ~/.config/discover/backendsrc
echo "snap=true" >> ~/.config/discover/backendsrcNote: the [Backends] section is required; just writing snap alone doesn’t work.
5. Restart Plasma / log out and back in