If your candidate isn't doing everything you want..

No, because you never know who the next tyrant is going to be. If we elected a fantastic president, then gave that person full dictator-level power, things might be really good. But eventually that person will either die or retire, and their replacement could be an insane mass murderer. But without checks and balances, we wouldn't be able to restrain that person, or vote them out of power. That's why Authoritarianism is always bad, even when the Authoritarians in charge are doing good things.

This is why even if I knew that Harris would do nothing as president, I'd still vote for her. It's just about keeping our checks and balances.