It's not terribly hard to write a Copilot GHA that does this yourself for your specific teams needs. Not sure why you'd been to bring a vendor on for this....

What do the vendors provide?

I looked at a couple which were pretty snazzy at first glance, but now that I know more about how copilot agents work and such, I'm pretty sure in a few hours, I could have the foundation for my team to build on that would take care of a lot of our PR review needs....