Seed money is the first to take the risk and deserves the majority share of profit
VC (series A,B,C) are putting in the most money and brining big hitters for the board and advisors. They clearly deserve the majority share.
Founders do all the work and it's their idea so they deserve all the money.
The second generation leaders productive, operationalize, and bring legitimacy to the company, so they deserve all the money.
Whichever group has the leverage forces the table to tilt their direction.
It doesn't matter how good the potential is, how sure the victory is, how close the first breakthrough customer is, if you don't trust someone, or there's a slimy/smarmy vibe then just walk away. It's not worth putting in years of effort to have to resort to contract lawyers to get paid.