Keeping all of the Trump-era “maximum pressure” sanctions in place has been the major error that may very well end up dooming that effort.
With all due respect, duh.
If Biden wanted to return to the JCPOA, he had ample opportunity to have done so and would have done so.
Instead, Biden has made sure that the political forces in Iran that wanted to make a deal, that wanted to trust the West, are discredited, leaving the hardliners in charge. This is entirely intentional, and makes sure that no deal will be done.
As always with Biden, ignore the splashy headlines and read the fine print.