It seems like you may not understand how budgets at the federal level work in the U.S. Congress passes spending bills and the President signs (or vetos) them. This has nothing to do with the debt limit as such. Eliminating the need to vote on a debt limit will not in any way lead to a situation in which runaway spending can occur that is not already present in the current system.

The grand bargain you speak of has already occurred. It occurs when Congress passes a budget that is signed by the President.