I just dump everything into its own note, then write some keywords to search for. Lots of small notes. Searching text is easy and fast on modern tech, so forget organizations that are inflexible and will need to change, just use text search for everything and put every thought into its own note.
Have an upcoming flight? Throw the entire email into a note ( i attach the email file, not contents), then write "trip SFO NYC november 2021 delta thanksgiving" and i can just search "SFO november" or "delta thanksgiving" and find the flight details.
I even keep a note called "addresses" so any service i give my address to i know about. Very helpful when moving (i do a lot) and tracking what accounts need to be updated.
I found the important thing was not to bother cleaning up notes, or tracking old ones or doing anything complex. Just let them exist, and when i get bored (eg. on flight) i may go through and clean old ones.
219 notes though, sounds like you already have a good habit of capturing your thoughts! Organizing tasks into current contexts has helped me a lot (At Computer, Housework, Wife,...). Best of luck!