PSB files can't be edited at all... And why can't I talk to anyone?!

Firstly, I have a 2.2Gb file saved as a .PSB that was able to be edited and saved fine before the move to 2021.  Now I open it and I can't merge layers, save, or anything.  PSDs are still fine but not PSBs.  Any ideas?

And secondly, I really need to sort this and have gone to the help page, but every single link I click just takes me back to the help page.  Where has the chat box gone? I just go round in circles...