The whole reason for fighting is that the American colonies were rich. Initially they had been propped up by the British. But, once the French were essentially wiped out, the colonists no longer had need of the British military, and they were now richer than the British, so they no longer wanted to contribute to the motherland and wanted to be independent.
The colonial governments had previously had influence over laws in that their elected officials would advise the governors. England shut that down. Patrick Henry made the “taxation without representation” argument ten years before the Declaration of Independence
Many excuses were made, that’s the one that stuck. The real reason was that the colonies were rich, and now had effectively unlimited land to the west they could expand into, that the British army had taken care of the French.
I think you have that backwards. The grievances were the motivation. The situation was the opportunity.
If they were content, they wouldn’t have revolted