Sorry to hear about the challenge. I know the Buffer Technology product and they are designed for the flexy polymer Glock frame. They are softer than the 1911 style shock buff.
Just a thought, maybe Buffer Tec. offers a harder urethane product for some of the other weapons it builds buffers for. If so, they might be willing to custom make a harder buffer for you.
Secondarily, you could mold your own. Urethane is available for home hobby use. You would probably have to fool around with the mix to get the correct durometer hardness.
Probably not what you wanted to mess with, but, we learn and then we do. That is what makes things better.