Dear One,
According to organizations that track voting records, Biden is a tick closer to the median vote, than center left. Which puts him dead on the spots as a moderate. Of course, he is more to the left than he was thirty years ago. As the entire political scheme has shifted a lot to the left. (My opinion is that this is the fallout of the neocons undercutting the true conservatives.) Most Republican senators today, are more left than Biden was when he started in the senate in the early seventies(!). If four decades is not enough of a track record to prove a moderate, than there likely never was a moderate. (Or maybe there is a slight chance that your own politics are polarized.)
Harris has not settled into a specific political platform. It is a long topic, but she has made herself comfortable with leftist positions, without comitting to said positions.