Or a way to trigger own user interfaces after a action which I did. So that I by my self can define. the content of the popup. And insert a search field, and further buttons with obsidian actions behind it?
You need tools and not shy from scripting.
My advice is to look up on Templater and Modal forms. Back in the day I mentioned both in this thread, where I showed some code how it is possible to add frontmatter keys and values on demand.
Show some of that to ChatGPT/Claude and cook away, experiment.
At the beginning I would be happy if I can create dropdown manus in a template section. I mean, I have to create the single templates anyway. But would not like to have to find my preferred, in a list of a thousand.
A few days ago I sent a link in the other thread for the Potato demo vault complete with the YouTube tutorial in which the person at one point shows how she selects from 3-4 templates in a pop-up suggester.