Or, looking at it another way, you're trading a person who has the ability to go against group consensus for the betterment of the community to a person who is highly incentivized to follow group consensus to maintain their power (in the ideal circumstances, of course; I'm ignoring the obvious failure case of corruption or other manipulations). When that group consensus aligns with your values, that could be good. When it does not - such as living as a political minority, or when the group consensus is harmful to you (take, for example, NIMBYism), that can be very bad. In both cases you will have no meaningful political representation. A Democrat voter in a very Republican county has no real voice in government affairs unless they expend an inordinate and frankly unreasonable amount of effort campaigning - and will likely suffer some social repercussions for doing so. The reason people keep coming back to the idea of autocracy - why companies are often so much more efficient than governments - is that a central decision-maker can (not always will!) more effectively direct group efforts and establish priorities.

Democracy, as has been said, is the worst political system, except for all the others, but let's not lie to ourselves and ignore that in some contexts it is, in fact, strictly worse. The classic example, of course, is an army led by direct democracy. When a thing must get done, and damn the consequences, then there really is no substitute for autocracy. It's just unfortunate that the people who eventually end up as autocrats are rarely there to benefit the community. Building systems of accountability and responsibility through culture and non-systemic factors may better this (see, for example, the 85 terms of Roman dictators who did not try to seize any more power than they had been given by the Senate and in fact often returned their powers before their term was over), but culture-crafting to accomplish that is unfortunately beyond us at the moment.

if it is a local government you directly vote for, that supports your argument.

Often, it is layers of government, way over you, who have no clue of the local needs, and it gets much worse.

Not only does it not know the local needs, it has no expertise in the subject area itself, and so an unelected unnamed bureaucracy rules the roost, and over time, gathers so much power, that regardless of which government comes to power, the true power rests with these bureacrats.

Accountability?

Who the hell wanted either trump or biden in the last election?

There is simply no choice because the political elites offered us this and we need to vote our guy not to let the other guy win.

The game is rigged and your vote is not worth much.

When you're buying a product instead you're effecting real change and telling society you want more of that. If only we could control law making in the same way we would have a decentralised society which better approximates what people want.