Indeed I think your comment on temps is valid based on many readings that show when synthetic oils break-down.
https://www.waynesgarage.com/tips/mo...0under%20loads.
The important part to consider is ensuring oil pressures remain good at those high temps. I'm not sure how engine parts and surrounding parts like to be at high temps like 270F for extended periods of time, but I'm getting convinced that the oil wouldn't be the weak point here.