I bought the book "Building a Second Brain"[^1] by Tiago Forte and its recommended PARA methods is well-conceived, directly usable and tried and trusted for me. There is even a follow-up book from him about PARA only [^2]. I recommend to check it out (you'll also find many resources in the internet without the need to buy a book - although I highly recommend it and it would be an appreciation for the author)
I'm a big fan of PARA method, but I only use it in my note-taking app. I tried to apply it to filesystem, but it didn't work for me. So I went with his philosophy of keeping it simple and what works for you.
[^1]: https://www.buildingasecondbrain.com/book
[^2]: https://www.buildingasecondbrain.com/para