There is a tool from Nx in similar space, where they cache test results based on code paths. They charge by hours saved, for example they calculate how long it

There is a tool from Nx in similar space, where they cache test results based on code paths. They charge by hours saved, for example they calculate how long it would have taken to run those tests and when they serve the cache instead, they charge money for it. Not sure if it could work in your case, but if it's saving hundreds of engineering hours, charge based on the saved time (and not on the normal runtime)