Yes it will have to be resolved by congress, but not in the way you think.
While you complain about the possibility of some low-skilled doctor using a drug off-label and costing BigInsCo money because it doesn't work, that is actually quite unlikely, and a far smaller harm than what is actually happening.
The insurance companies are overruling the medical judgement taken in the best interest of the patient by some of the highest trained and skilled physicians in THE WORLD, and using low-skilled nurses and doctors to do it.
Your premise that "asking them to distinguish" when the treatment plan is literally designed by some of the best doctors in the world is absurd. You really think that some doctor that couldn't cut actual practice and fell back on InsCo job, and some nurse are on anything like the same level as Mayo physicians? You are literally saying some just-out-of-college junior programmer should be hired to review & reject code over the judgement of Linus Torvalds or Bjarne Stroustrup. It's forking idiotic.
I've got close family members who have gone to Mayo Clinic for help with inscrutable disease conditions. And the insurance companies keep coming up with all kinds of BS reasons to deny. We're literally working with world leaders in the profession, who actually make headway on the disease when no one else can, and the InsCo dolts (who knows if they even have any kind of med license) try to declare some tests "medically unnecessary" or deny on some other pretext (e.g., "you didn't call three days ahead for approval"). Literally, who the f*k are you to question the literal top docs in the world?
In short, insurance companies are systematically scamming, committing fraud, and murder for profit. You can meet all the terms of their contract, make every payment, but if their systematically running software detects that you have a condition or expense profile that puts you in the top 5-10% of expenses, you will get "reviewed". And they will literally do anything possible to deny and delay your payments and therapy, even if you die, just to increase their profits. There was sworn testimony before congress by an insurance employee who "saved" $500k by denying coverage to a patient who died; she was promoted. for that. It is literally defrauding the customer, accepting payments for services you deliberately and systematically have no intention of providing, and denying those services resulting in death, all for your profit.
Putting incompetent gatekeepers in the loop with a profit motive to harm or kill you is at this point, obviously harmful.
It should be up to the physicians alone to determine medical treatment. Period. Full Stop. Insurance companies should be banned from gatekeeping.
If gatekeeping is allowed, it cannot be in the current form of "just deny coverage because we don't like it"; it needs to be at least provide a better treatment plan that produced documentably better results (and no, you can't suggest one that the patient's docs already tried and didn't work). The result would be either no gatekeeping or the ins cos will need to hire actual highly skilled physicians who act as a true 2nd opinion team, which would be a step up from these ignorant gatekeepers.