Howm has a simple solution for this: Links like “>>> this thing” searches for “this thing” and opens a search buffer. The top hit is already marked, shown in a preview window below, and can be opened by clicking enter. But if you want a different result, you just navigate that search buffer to find the hit you want.

The search triggered by a link is sorted such that it shows first “comefrom links” (if any file has said explicitly said that “these keywords should lead here”), then headline results (files where your phrase is in the note title), then siblings (other notes that link to the same keywords), then fulltext search matches (any file that just contains those words). So if you have 0 results with those keywords in the title after renaming a note, you might still find the note again via full-text search hits below. If you have 2+ results, just navigate between them with the arrow keys while previewing their contents, and open the one you want.

This design is intentional: The author advocates to “write fragmentarily, read collectively”; so instead of refinding an old note and adding to it, you can make a new note with a similar title where you capture new info, and then links will point to both notes from now on. (In most cases, if their titles are similar, the contents are likely relevant in the same situations as well.)

With that said, Howm supports exact links as well: You can link to a file path instead of a title. Since Howm defaults to putting just the creation datetime in the note filename, the filename is by default like an immutable-ish UUID, and such links should remain exact as long as you don’t manually move or remove a file. By default, Howm creates such links in one context: If you create a note (C-c , c) while inside another note, it saves an exact back link to where you came from so you can remember your “inspiration”. But you are of course free to use such links everywhere instead of the “fuzzy links” above if you prefer.

> How does this deal with searches that, over time, can change to return 0 or 2+ results?

You can put more than one search link in currently edited note, than test all of them and at one point you will learn how to formulate search query so that you would recite yourself exactly as in that note that you want to see just now.

Also you would find more suitable titles while being in this process, but it wouldn't be for long.