There have been recent improvements in health care pricing transparency.
Insurers always pay a negotiated amount. Far less than cash pay, but more than Medicare. One hospital I used to work at offered discounted cash pay packages, especially for maternity and newborn care. A high number of their patient population came from the local Amish community and were uninsured. Many Amish delivered at home but some needed a C-section or had pregnancy complications and these packages were very useful.
In 2019, a federal law took effect requiring hospitals to publish their charge master, or charges for every procedure, including hospital stay. However, I believe it only shows the retail amount. One of our local health systems allows you to put in your insurance information so you know what your insurance will pay. CMS sets the Medicare rate, and insurers negotiate a percent of that (e.g. 150%). Not all hospitals are compliant with the transparency law, however. And most act like they are doing you a favor by publishing their fees, instead of admitting it’s a federal law.
You can find this information by googling the health system and “fee schedule” or “charge master”. Another improvement nationwide is the elimination of out of network surprise bills effective in 2022.