You’re missing the point: it doesn’t matter who claims what. Congress HAS funding authority if they use it, but they can only use it with a budget.
I can give you two examples of how this works: Under Reagan, EPA head Ann Gorsuch denied Congress certain docs (supported by the AG).
Congress, which had a budget at that time, just simply shut down her budget line, and within weeks she produced what they needed.
There was an almost exact duplicate of this under the Nixon administration (can’t recall if it was EPA or something else), but again, as soon as MONEY was invoked, Congress had power.
Sessions is irrelevant from the standpoint of stonewalling. It’s CONGRESS’S fault for cedeing power via not doing budgets. Blame them.
That may be the structural fix that's required, but the immediate problem is the fact that Trump's DOJ is willfully obstructing Congress.
Chaffetz points to Attorney General Sessions as the person responsible for this debacle and I see no reason to doubt him.
It should be obvious: three equal branches of govt - and the power of Congress is the power of the budget, which must originate in the House of Representatives.
When the H of R gives up the power of the purse strings they have ceded all their power and authority. That is why the bureaucracy (DS) is beginning to be the government. Congress even ceded their authority to write laws to the DS, and now they wonder why they have such little control... THEY GAVE IT UP!