SUMMARY
Often, when searching with Discover you won't get related search results. In example if you search obs you will have a very long list of unrelated packages (no obs studio isn't there), and after all the packages in the repo it will list "obs studio" flatpak.
The issue is that the obs studio is found with a simple "dnf search" via terminal (if you have rpm repositories enabled).


STEPS TO REPRODUCE
1. On Fedora, enable the rpm repositories and also the flathub repo
2. Open discover and search "obs"
3. In alternative to point 2. is possible to type in a terminal "plasma-discover --backends flatpak-backend,packagekit-backend --search obs"

OBSERVED RESULT
In both cases you won't see obs studio among the first results. And only near the end of the long list you have one obs studio but is flatpak.  

EXPECTED RESULT
obs studio as first result, and the ability to change the source from flatpak to repo

SOFTWARE/OS VERSIONS
Fedora 35
KDE Plasma Version: 5.23.3
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
If you search "obs studio" with discover or "obs\ studio" with the terminal command written above, the results are more pertinent but still only the flatpak is shown. 
Bonus: if you search obs studio in the terminal with "appstreamcli search obs studio" it won't list obs studio as result but blender 
NOTE 
For convenience this was reported with obs studio, but I would expect this behaviour to affect other packages as well