If Harris were as off the mark as some of the commenters below believe, I don't think she would have passed the intensive vetting she was given or been chosen over the other highly qualified candidates. The facts will out, don't worry.
The running mate's job is to prosecute the case against the opponent. Harris has already begun that work, and I don't know who could do it more effectively. She takes the Don apart in words that even he can almost understand.
Biden's going to step aside in 2024 and give us our first woman president. Between now and then, we will be treated to a show of all the things we used to take for granted--competence, dignity, compassion, and commitment to American ideals.
Perfect? No. But perfect for this moment in our history. Complain about her flaws, but campaign for the ticket like our lives depend on it.