Biden had his mental issues - in terms of the quickness of his thought processes for example no doubt - but clearly not to the point where he could not have stepped up and done something - if associates were doing things that he didn't want done.
The extent of his pardons were not ideal - the power was abused somewhat - but I think he correctly saw Trump's nature - and that if Trump could go against his family and other good public servants people such as Fauci he would. Most if not all of the allegations against those pardoned were iffy at best - mainly based on conspiracies - with the possible exception of Hunter.
I don't like to do a - but Trump - but Trump's recent pardons are truly appalling - people who ripped off the small people, nursing homes, people whose family donated large amounts to Trumps campaigns, people who were supporting him but clearly did really terrible things, and did not deserve a pardon.