Rules were unfinished - they were trying to rewrite a second version after Republicans kept blocking it in court. The unfinished rules already had republicans threatening to sue about it. Presumably ran out of time to complete it

He’s still looking at other more narrow areas that are less able for Republicans to make BS challenges on

Biden is still pursuing other avenues for debt relief before his term is up. On Friday, his administration announced an additional $4.28 billion in debt relief for 54,900 borrowers in Public Service Loan Forgiveness — a result of ongoing improvements to the program. Despite not being able to pass broad relief, Biden, over the course of his term, has provided relief to nearly 5 million borrowers through changes to various programs.