A pardon didn't go so well for Gerald Ford and Richard Nixon as you recall.
Consider, too, all the people who went to jail for taking classified documents and it will only make it clear that those who are rich can escape real punishment. It may well be that Trump is only running for office to escape the possibility of jail one way or the other. And take the donations and run.
A pardon worked out just fine for Ford in the long run - history views him much more kindly for it than his contemporaries did. Sometimes, you have to do the right thing for the greater good. Ford knew that. I hope Biden would as well.
Biden’s play, if he wanted to be a true statesman, would be a conditional pardon of Trump for all federal crimes (nothing he can do about state charges), and then an announcement that he wasn’t going to run in 2024.