I can't speak to the other apps, but Evernote does NOT support custom URL schemes.
the best you can do is to have a KM Macro that will select the line the kmtrigger url is on, and then use a KM Open URL Action.
after reading @JMichaelTX 's response, I realized that I had copied the trigger but not set it as a trigger in the macro.
After doing so, it works fine and opens up a whole new world of KBM user interface options in addition to Palettes and all other triggers. It is rather amazing in terms of the ability to improve formatting and display, and add explanations pertaining to certain macros.
I wonder if I perhaps accidentally stumbled upon a new approach to triggering macros.
@ronald, I'm not sure I understand what you did.
Are you saying that the kmtrigger URL is working from Evernote?
There is no way to "set it as a trigger" in the macro. You can open up the "or by script" and copy the url, but that does not "set it". There is no need to set it. I tested the kmtrigger url in TextEdit and it works fine, but not in Evernote.
You are right: it does not work in Evernote. Sorry for misleading you.
I was referring to using URLs in Bear.
I use Evernote as a PIM when I have to store my data in its final form or to capture the web.
For ongoing daily tasks, I use Bear which is better IMO because of the editing capabilities, a multitude of export formats including many copy as options, floating windows, multitude of Callback URLs including a URL callback generator for each callback (https://bear.app/xurlbuilder/open_note/) , ease and speed of transferring the final draft to Evernote and now as a supplementary form of KBM UI interface (in addition to, not instead of palettes), ease of creating links (just type [[ and type any word in the title → a pick down list of all notes appears, very flexible multi-level lists, multitude of headers, ease and speed of writing using Markdown)
That being said, I would never for a minute imagine replacing Evernote with Bear to store information.