T-Mobile Experts aren't experts. What can be done?

Regarding the issue mentioned above where I asked about adding the ONE Plus to the T-Mobile ONE Unlimited 55+ plan, after not finding the discounted rate for +2 lines in MY T-Mobile app.

T-Mobile Expert Marygrace told me, repeatedly, over two hours of a chat session, how the discounted rate only applies to "Family Plan" accounts, I have finally found in a search where the term "Family Plan" is a valid reference only in regard to the Simple Choice accounts, and, as I suspected, has no correlation with any of the T-Mobile ONE accounts, nor, with the ONE Plus adder I was interested in.

This "Expert" was confused about which options apply to which plans and was unable to grasp the concept that THEY MIGHT BE WRONG in order to actually help the customer. Despite my leading her to published websites describing the discount and to which accounts it applies and her being unable to provide any link to support her stance on the matter.

This complete waste of time for both of us is exactly the sort of thing that exemplifies how their expertise is often based upon one misunderstanding after another. It is rare that any "expert" has not left me feeling as though they think I'm the bad guy and their defensiveness toward their misunderstanding of current plans is somehow justified enough that they won't question their own competence. (look up the Dunning-Kruger effect to better understand such a mindset)

A restructuring of the support channel that would include accountability regarding issues, and, that can be mutually accessed by both "experts" and customers would solve this.

Thoughts?

Comments regarding other's experiences when multiple calls for a single issue are essentially echos of the previous call that netted no resolution?

Can these suggestions reach someone at T-Mobile who is in a position to consider and implement them?