Why did Joe Biden and Kamala Harris receive more bipartisan support than Hillary Clinton got in 2016?

A lot of Republicans like Larry Hogan, Jeff Flake, Cindy McCain, Liz Cheney and Adam Kinzinger gave support to Joe Biden in 2020 and Kamala Harris in 2024. Why didn't Hillary Clinton receive the same Bipartisanship Endorsements in 2016?