Hey @seanchristians and welcome to the community,
Very good point here, I definitely understand the need for better granular control for billing access especially in the case you and others here presented.
Nothing official yet and I am just speculating here, but with the latest web-vault release v2022.11.0 now provides a dedicated Billing section for an Organization.
Given that there is currently a custom role for Access reports, this new dedicated Billing section may be the first precursor to adding an additional custom role which will allow for only access to the new billing section and complete this request.
Let’s hope there is more to come soon