You seem to think that the population of California dwarfs the rest of the country. It does not. There is no way that California could lead the country around by the nose the way less populated states are doing right now based on the two senators per state regardless of population system we have in place today.
The results of unequal representation and minority rule in the U.S. Senate ripple out and have many disturbing political effects. First, and probably most obviously, this kind of Senate often produces policies that disproportionately favor less populated states and their citizens. For example, many of the least populated states, like Alaska, North Dakota, South Dakota, and West Virginia get much more back from federal programs than they pay in federal taxes. While many large states, like California, Illinois, New Jersey, and New York pay a lot more in federal taxes than they get back.
More importantly, because of its undemocratic nature, the Senate has become the graveyard of many policies supported by the majority of Americans. This questionable tradition goes back far into the previous century. The Senate blocked ratification of the League of Nations treaty after World War I, stalled anti-lynching and civil rights legislation after World War II, and killed the Clinton universal healthcare program in the 1990s. More recently in 2019, the Democratic House passed a whole raft of bills supported by most Americans on the issues of gun control, global warming, equal pay for equal work, controlling violence against women, rebuilding vital infrastructure, lowering prescription drug costs, preserving net neutrality, and voting and campaign finance reform. All were killed by a Republican Senate whose leader, Mitch McConnell, bragged that he wanted to be called “The Grim Reaper.” If you are wondering why the U.S. lags behind most of our peer democracies in all of these policies areas, the minority-controlled Senate provides much of the answer.