Wanted to post some sites that address the "who is the most progressive" question.
Some people had mentioned it, and though it may be surprising, Kamala Harris is usually ranked as more progressive/liberal than Warren.
On GovTrack, Harris is ranked as the #1 most liberal senator, followed by Bernie at #2. Warren is #26:
Year-end 2019 legislative statistics.
www.govtrack.us
On ProgressivePunch, Harris is ranked the 2nd most liberal, and Warren is the 5th:
ProgressivePunch is a searchable database of Congressional voting records, from a Progressive perspective.
progressivepunch.org
So I think this notion that Harris is not "progressive enough" is unfortunate, because her voting record certainly suggests otherwise.