I think that just as it's important not to fully level blame against Trump for a pandemic that may have been horrible in this country anyway, that 4 year measure isn't as important as it seems at face value (which isn't me admitting my life was better 4 years ago; I would actually say the opposite is true in pretty significant ways for me.)
Going back to Obama and Bush for example, I don't really believe that 4 year metric says much at all. Obama inherited a nightmare, but even Bush doesn't bear full responsibility for everything that happened with the economy. The state of the country in 2012 wasn't amazing, but I still think Obama earned reelection and that he likely proved better for the job than Romney would have.
Of course the economy and gas prices and inflation are each important issues, but I don't believe that the president bears as much singular blame for the state of those things as many argue. In some ways, I think that Trump's actions in office insured that Biden has challenges to overcome. But in other ways, I think the issues that Biden has faced in office are deeper than any one person and can't be fully blamed on Trump.
A lot of what more moderate Republicans argue about Harris I think has merit. She definitely has a questionable past, and I think her administration will have issues. I think I've said similar to you before, but it still all just strikes me as a drop in the bucket by comparison. Maybe not absolutely everything that Democrats claim about Trump is gospel, but much of it is caught directly on footage. The rap sheet of very real vices weighing down his candidacy is just too large to quantify. I'd hardly know where to begin. Even setting aside absolutely all crimes and government overthrow attempts and heinous things he was caught saying and doing (which really aren't issues that should be set aside), I just don't believe there are decent human beings that conduct themselves in the way that Trump does.
As always, thanks for reading and taking the time to thoughtfully explain why you disagree.