After trying so many kinds of note taking apps. I finally keep coming back one that at max supports Markdown (actually I don't need it, but I can tolerate it) and handles plain text files and give me direct access to those plain text files.

> clearing my "inbox" of quickly taken notes

I always have a note pinned on top called "Clipboard". Sometimes I name it "Snippets". Earlier I used to call it "Jottings".