It would be nice to have external links that magically work everywhere and don’t rely on any app-specific functionality but I feel we are looking for a complex solution for a rather simple problem here.
There is an easy 100% bulletproof way to refer an Obsidian note in any app or even on a piece of paper. It worked for original author of Zettelkasten and it works even better with computers we have nowadays. It does not depend on any databases, URI schemas or paths.
All you need is a unique ID anywhere in your note. You use it in a plain textual form anywhere you want to “link” to that particular note. Then you use search to find it. It’s only marginally more cumbersome than a link but it’s infinitely more reliable and future-proof. It can be automated to some extent too.
Personally, I use a YYYYMMDDHHmmss ID in my YAML frontmatter. When I see such an ID in another app, a click to select it and 1-2 shortcuts take me to an open Obsidian app that has already found a note I wanted to see. Works on my tablet and phone as well, although with slightly different mechanics of course. And if I give up Obsidian, none of those connections will be lost and searching will remain just as easy.