I would personally love more information on this topic. I view elections for Congress to be much more important than presidential elections.
Looking around I found this website via her Wikipedia entry. It’s a website that measures how close a member of Congress votes with Biden (but only from 2020 to 2022) and Sinema and Manchin seem to vote with Biden on nearly everything he wanted. My personal opinion is those two senators along with Biden act as the “centrists” (right of center) that we expect them to be.