This is a highly customizable desktop widget tool that can display various types of information on your desktop, including text notes. You may need to use or create a skin that supports displaying text files.

What’s on your desktop?

Rainmeter allows you to display customizable skins on your desktop, from hardware usage meters to fully functional audio visualizers.
You are only limited by your imagination and creativity.

Rainmeter is open source software distributed free of charge under the terms of the GNU GPL v2 license.

There is a skin on GITHUB display

Can be used to display Obsidian notes.