What really sucks is that no one will try and perform a $300-400 vulcanizing repair on an expensive tire. I don't know if it's a liability issue on the repair shops that they are afraid of or they worry about sudden failure causing a problem which is so much different on a low speed off highway vehicle. I have seen so "farmer" sidewall repairs were heavy cordage was used to stitch sidewall back together and then multiple boots glued into place the repair and protect the inner surface of the tire for the tube.
And there is this outfit that has external sidewall kits for non highway tires.
Agricultural Use
If I have another large tire issue I am likely to try these, hope I don't need too.