Hey @oxyymoronn, thanks for reaching out and sorry to hear about the difficulties you've had with accessing your save file on PS5 console.
If I understand it correctly, you've been initially playing on Xbox One, is that right?
Starting new save will result in cloud saves being overwritten, therefore the reason why your save file may have not appeared when you launched the game on PS5 (which then resulted in you starting new game) is due to updates not being fully installed (at the time).
I do understand that you do not have easy access to your Xbox, however you can try and see if your previous save file is accessible through console's cloud, however if not and you're unable to see your save file on PS5 anymore, I am afraid our Support team would not be able to provide any assistance in such case.
Should you have any further queries, let us know!