Pending a more informed answer, I doubt there's a problem with search. Searching for "Alamar" returns both editions of your game, which means they're listed. On the other hand, searching for highly generic terms like "wizards" or " role playing" is likely to return your game buried under many other results. Doubly so as free-form searches cut off altogether after a few dozen results, as you've noticed. Try looking under the role-playing genre instead, but be prepared to browse through lots and lots of results. We do have over 150K games on Itch.io by now, and a lot of them must be RPGs and/or about wizards.
Itch.io as designed tries to give as many games as possible a chance, but with so many of them uploaded, the software can only do so much. You simply have to advertise in other venues as much as you can, in addition to here.