It would be up to Congress to make something that couldn’t simply be reversed, but I wouldn’t say now is the time for that since the GOP-controlled House almost certainly wouldn’t pass the bill, even if the Senate did. Biden can only issue executive orders that can be reversed on a whim.
He can’t tackle SCOTUS expansion unless we also vote in a solid majority in the Senate, and he can’t tackle Medicare for All unless we vote in a supermajority.