It is right after the full immunity clause in the Constitution.[joking]
The Supreme Court has already ruled that Biden doesn’t have the authority to do this. See Biden v Nebraska https://www.supremecourt.gov/opinions/22pdf/22-506_nmip.pdf
The legal basis for this forgiveness is different than the one the courts ruled on. In this case, the Dept of Ed was given discretion on applying forgiveness in certain loans and situations. It requires a rulemaking process that includes public comments all of which take some several months.
The strategy of the forgiveness that the courts ruled on was in my mind done knowing two things. One that it would likely fail and two everyone's attention would be watching the wrong thing (kind of of like a magician act). It worked perfectly.
My current guess is they want to get ahead of the Chevron opinion that will curtail the power of the regulators.