It’s 1911, and you’re in the UK. The Liberals have a large majority in the Commons, but things are not going well, and an election looms. They decide to change the subject by sending the Lords a budget they know will be rejected. When it is, they get to run against the Lords instead of defending their record. It works, albeit imperfectly; they win the election with a reduced majority.
Biden is clearly attempting to avoid this kind of scenario. He wants to talk about empathy, the virus, the economy, climate change, and health care. If the election is fought on those grounds, he will win. If it becomes a battle over the Constitution, who knows? Hence his lack of interest in committing himself to abolishing the filibuster and packing the court.