How can I easily find a song by an artist?

But you see what you’re saying. In order to constrain the search to only songs by Puscifer, Roon has to know every song by every artist in your library and also any streaming services you may have. Maybe Roon has that capability, I don’t know. I don’t have Puscifer in my library and it’s not in Qobuz, so I can’t emulate your search. All I know is it’s not a trivial effort to provide a track level search for literally millions of tracks.

And that is exactly what Roon should do if they cannot find a track:
emulate
They should themselves launch a search call both in Qobuz and Tidal and work with the returned result to eventually look again in Roon, or return the Q/T result to the user.

I see it differently.

If I search for Puscifer ( or the Beatles, or The Stones), Roon can bring me all of their albums with no issues.

I know nothing about how database searches are done but but I assume it doesn’t search tens of millions of songs and find all of the songs by the Beatles and then find all the songs on Sgt Peppers and then collate them into that album.

So it can already constrain the search by artist.

So once it has brought in the miniscule subset of albums by Puscifer, surely it’s trivial to then search within that subset for a single song

Some inconsistency here, it seems. Roon doesn’t give me the same result as you (and I’m not aware of any censorship enabled on mine!)

Naim gets it right:

cid:7985AFA8-7833-4384-8243-EE2EA17415EC@Home

Tidal gets it right:

cid:CCB95630-166B-41B1-9359-98C490C6FB9D@Home
Qobuz doesn’t:
cid:64F26A76-C06C-494D-98B8-F2B0AD319C21@Home

Does Qobuz have the album? If not, the problem could be in Roon, for not combining search results from Tidal and Qobuz (I presume you have both).

I don’t have Qboz, only Tidal

To be fair to Qobuz, they don’t have any Puscifer, which may be seen as a shortcoming, but you obviously can’t blame their search for that. Roon, on the other hand, should be able to find it as a Tidal track. (I am temporarily running both, while contemplating a move from Tidal to Qobuz.)
If you find Puscifer in Roon, you can find the right album, and the track is there, so it should be there in the search results under Tracks.