Read the Constitution.
There are no restrictions, indeed, there is a Section calling for Regulation of the military by the Congress.
But, hey, you go ahead and believe counter to the Constitution.
“Congress is authorized to: raise and support Armies [and] provide and maintain a Navy;” furthermore “To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions” and “To provide for organizing, arming, and disciplining the Militia, and for governing such Part of them as may be employed in the Service of the United States;” finally “To make Rules for the Government and Regulation of the land and naval Forces.”
I’ll ask again, since you ducked the question: If Congress set a restrictive ROE, would that supersede the orders of the CINC, in your opinion?
In short, who runs the battlefield, the CINC, or Congress?