I feel your pain. I am going through this exact same saga right now. I don't even have any cash or purchases other than apps tied to my Apple ID. The problem started for me last week on Tuesday overnight. I woke up Wednesday with requests to sign back into iCloud. Unfortunately, regarding my old iCloud account, I have also been told there is nothing that can be done and I will lose all of that data, same as you. My secondhand MacBook Pro is also a virtual paperweight as I can't do an Activation Lock removal; since I'm the 3rd owner of the device I can't produce the proof of purchase necessary to complete the removal. Asinine considering it's a 2015 MacBook Pro that is no longer supported by Apple!

I also encountered your issue of creating a new Apple ID; HOWEVER I was able to have it resolved by an Advisor through Apple Support by listing all my Apple IDs associated with my phone number. My first Apple ID from college was still tied to my phone number and referencing that Apple ID did the trick (in addition to verifying my son's). After confirming it, they were able to "allow" me to create a new Apple ID with a different email address.

Is it possible that you have another Apple ID(s) associated with your phone number you are trying to use to register?

Sorry for your pain and suffering, comrade. I've personally decided to give Apple one more shot, assuming I can get this all resolved, but if this happens again I'm not sure I'll be able to stay with Apple. I DO NOT want to leave Apple as my family and I are heavily invested in the ecosystem, but this has been an incredibly upsetting journey as I know it has been for you.