I want to offer an alternate perspective: stop wasting time trying to make notes with links, charts, images and fancy stuff like that. Your Second Brain doesn't need any of that, it just needs the text to jog the memory. Your brain is better at a lot of things than your Second Brain will ever be.
Keep your notes in markdown format or with no markup at all. Organize them into proper folders. Put the top level folder in Dropbox or use Syncthing. The Dropbox mobile app has a built-in text editor. For Syncthing, you might need a plain text app on your device.
For quick notes like you mentioned, use a small legal pad style notebook. At the end of each day, type up all of the notes you took. Make sure those notes end up in the proper files / folders. Throw those pages away and start the next day with a fresh page.
If you want an even simpler system, some people get by with a single text file.
This system is neither inferior nor superior to a system like Notion, what matters is the habit of note taking. I do believe this system has lower friction / maintenance costs though. To me, Notion seems far more like a tool for curation/presentation than it does for friction-less note-taking.
Just my two cents :)