Fair, but the biggest mistake by far was failing to take charge of the immigration debate. The second biggest was his press secretary's insistence on announcing that everything was fine in the economy over and over as a distant second. Third was not resigning when it became clear that he couldn't really keep up with the job, or at least not trying to run for a second term. Virtually nothing else matters by comparison.
Fear over economic damage due to immigration is perhaps the last remaining unifying force among the American political right wing. Biden actually did a lot of good things as president -- arguably a lot more good than he did in his time as senator. But his administration was too eager to just run the federal government as a quiet meritocracy and avoid dealing with any of the hot political issues of the day. He and his administration fucked up so bad that now not only is most of that good undone, but we are in a dire existential situation, facing generational-scale damage that might be unfixable.
It's one thing that they genuinely fumbled the handling of the huge immigration/refugee waves spanning the entire continent and it took them well over a year to start coordinating a response (which they never really did apart from eventually just closing the border) -- it's another that they kept trying to insist everything was fine, there was no problem, there's nothing to see here. People were freaking out about it all over the country, and of course they were being heavily propagandized, but that's not the point. A strong and proactive White House would have made all the propaganda look stupid. Instead, it looked like the truth.
It's absolutely mind-boggling to look back on just how weak the president had to have been from 2020-2024, to somehow let the party of Jan 6 and the disastrous handling of the Covid-19 pandemic regain enough control of the political narrative to make Trump seem like anything other than a narcissistic mobster.