What I want is a Linux GUI tool, that on a hot-key pop-up and allows me to quickly add comments/task/edit using only keyboard, and then when I hot-key it again, it hides in the background. Any recommendations?
For more substantial notes work I typically switch to the appropriate virtual screen, switch to the GUI-mode emacs there, and if needed use a hotkey to jump to the appropriate org file.
The most usable one (and the one I use would be a tiling WM).
Another would be dependent on the desktop environment you use. KDE has KHotkeys. Gnome certainly something similar.
Another more independent solution would be ror scripts (run-or-raise). They start or run a custom command with a key stroke.
https://extensions.gnome.org/extension/1336/run-or-raise/ https://github.com/mkropat/jumpapp