Yeah, two big mistakes Bidenand the Democratic party made
First, Joe should have bowed out gracefully in 2023, allowing for a full primary and general election
Second, he and the Democrats should touted their successes more. Joe pulled off a minor miracle righting our economy within four years, especially considering what a disaster Trump left. He was the right man at the right time for this job. But all of his success went under the radar and was drownedout by right-wing screaming lies 24/7. He, and the party needed to be more forceful, more vocal in publicizing those achievements.
Bonus mistake, Democrats need to master social media, develop a podcast presence, a Tik Tok team, etc. Obama started this, but after him it just kind of faded into the background. It can still be done, but there's a lot of catching up to do.