I use Keep for checklists and disposable notes, and Joplin (similar to Obsidian, but open source) for my “forever” notes. I look for apps that give you the option of exporting notes in a common format (currently markdown), and I have notes that have followed me through several changes of note taking programs.
You’re already using Obsidian, so my suggestion is… Take notes! Take notes on cool software you’ve discovered, take notes on your settings and configurations, take notes on any issues and bugs you’ve had to fix, take notes on how to use unfamiliar programs, take notes on Linux terminology. You have a huge personal knowledge base from years of using Windows. Linux is not hard to use, but it takes time to become second nature to you.
They can have him. He’s already done far too much damage here.