Republicans make gains in the House, but what about the Senate?

[AgnosticBoy]

2020 election polls showed that Democrats would pick up seats in the House and Senate, but they've actually lost seats with the Republicans picking up 5 seats in the House and will likely keep their senate majority. The implications are staggering in that now Democrats may not be able to add to the Supreme Court nor get their full agenda passed as previously thought.

Will the Republicans keep their majority in the Senate?

Will a divided House and Republican majority Senate create a problem for a president Biden?