Sorry folks, you’re looking at it backwards.
First thing: Cut out ALL non-Constitutional spending.
Cut out ALL Federal functions not explicitly outlined in the Constitution.
Only then can we find out what the bill is for services rendered, and THEN equally apportion it among the people.
Apportion the taxes based on the population of the states, that is.
“ALL non-Constitutional spending”
There is no such thing as “non-Constitutional spending”.
Congress has an unlimited power to spend:
“The Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States”
Article IV, Section. 3.
“The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;”
Article I, Section. 8.
Congress has somewhat restricted taxing power, but it has unrestricted borrowing and asset sale power.
Our Constitution has flaws.