My organization keeps evolving and is somewhat liquid. Even though I am using a no-longer identifiable version of PARA aka what works for me. I have found the best thing to do is just start working and see what happens.
Are you sure you need all of your older notes? (I have no idea, just a question you may have already answered).
How often do you refer to those notes? Are they mission critical or nice to have?
Once you know you need/want the notes, understand you are not tied to a four folder structure. Your vault is a folder, you can add/delete files and folders. In my opinion no system will be perfect, because it will most likely continue to evolve. All any of us need to do is find the perfect system for us.
Hope this helps a little.