I would agree, as far as his policies go. But he made two disastrous mistakes. One was not to pursue Trump aggressively for his crimes, because Biden thought Trump would fade and disappear and ignoring him would be a way to heal the divisions in America.

How was that Biden's mistake? The President isn't supposed to directly oversee the prosecutorial decisions of the DOJ. While Trump doesn't seem to observe that law enforcement independence, it's certainly something that the Democrats fiercely advocate for and argue was honored during the Biden administration. That would be DOJ's call. And DOJ eventually did prosecute Trump, which didn't seem to result in anything that Biden or his supporters wanted.

Plus, Biden made some mistakes in his policies, too. Exhibit A would be the Build Back Better/Inflation Reduction Act, which (with benefit of hindsight) went way too far in delayed and long-term spending, made a serious mistake in having the ACA subsidies be short-term rather than permanent (assuming incorrectly that the GOP would be forced to go along with extending them), and IMHO put too much of the spending (about 44%) into energy and climate programs. And of course, the Administration's lack of response to inflation - Team Transitory - was political death.