At one point in my search I just quit responding when broker requirements became too much. Buyer profile or PFS… fine. Anything more than that probably wasn’t going to be worth my time.

i usually just sent my lenders preapproval letter.

i learned really quick that the harder it is to get the CIM the more likely there’s something to hide there.

one broker completely wrote me off during a call. It was for a business selling for less than the business im current approved for. Oh well, his loss not mine.

Seller information is mega million times more confidential than buyer's PFS. Bank letter is valuable but is not a substitute for PFS. Banks do not have to follow any standard for pre-approval letter.
Banks issue Term Sheet after the LOI is signed. Hopefully the broker and seller have done enough DD of the buyer before signing the LOI.
In my personal practice, of 35 years I have asked for PFS <1% of time and that too if seller asks and likes the buyer. I have other ways to test buyer's ability to pull off a deal. Not everyone gets the CIM. If a buyer has an "attitude" it helps reduce the CRM size.
Having said above, there is a learning curve for both broker and the searcher. Hence both need to respect ech other. Supposedly, searcher (most, not all) has more maturity