if you have a gmail address for exemple you can open a infinit new accounts with your same exiting email with their system of testing adresses.
For exemple yourmail+01@gmail.com yourmail+02@gmail.com yourmail+199@… will all be link to yourmail@gmail.com gmail address.
So even if your main Fusion account expires you can still get all your project in readonly and create a second fresh account based one your existing email address, autodesk doesn’t detect it.
I had the same renewal issue and i ended on with that trick for a new account, not ideal but forever free over the years.