Think of shareholders like voters in a not-very-well-functioning democracy. They hold ultimate power, but don't get to vote on things that often and certainly not on every decision. So their power gets exercised on big lumpy things like restructuring the cap table or executive appointments. Big shareholders may well be informed or even consulted about big decisions though, and have informal opportunities to make their general feelings known by meeting senior management. If the shareholders are unhappy they might orchestrate a rebellion and block executive comp or vote on some independent board members or whatever.

The board is like the legislature in a parliamentary democracy. They are accountable to the shareholders because they are appointees, so if the shareholders don't like what they do they can give them the boot and appoint someone else. Likewise they can fire the executives if they need to, and also get a vote about a wider range of issues than the shareholders. They therefore have more direct control than the shareholders, but its still not at a very granular level of detail typically. Or if they are going super granular on one topic they are really zoomed out from everything else (and giving the executives more latitude in those areas). So I have been at board meetings where there is a 100 page board pack and the entire conversation has revolved around a microscopic discussion of one page, with everything else being skipped over.

Then the c-suite are like the executive branch. They deal with the day to day and actually have to get things done. On a daily basis shareholders and the board will generally leave them alone unless things are going poorly (in which case the eye of sauron is on you).

So hopefully it follows from that model that you actually have a lot of leverage as an executive and a lot of latitude to make decisions within a general strategic direction that has been agreed by board and shareholders. Secondly, shareholders are not a uniform blob of faceless avaricious beasts who care only about profit - institutional shareholders will have their respective shareholders and issues like reputational risk etc to consider. As an exec, you can often use credibility you have built up to persuade them of a particular strategic direction and they may or may not give you leeway depending on how much you have delivered in the past etc.