Surely you must be joking?

The government entity that makes all the laws and decides how the money is spent, can’t allocate funds for their core purpose?

Individual lawmakers may not want to, but they can if they wish to.

There are already government departments that can be used and believe it or not, there are actually people who can write public tenders without undue favoritism.

A single lawmaker should obviously not have an unlimited budget, but the legislature as a whole should have access to sufficient funds to make laws fit for purpose.