Love to hear more of your perspective. I’m trying to keep temps that low intentionally.
From what I’ve read EGT >1250 is the danger zone. Is your main concern the potential compressor degradation or...?
My 4BD1T saw 900C (1650F) several times when I wasn't paying attention (towing, dropped off boost etc) and I routinely ran it at 750C (1380F) sustained for minutes at a time.
It didn't give a damn. I have since rebuilt the engine (for other reasons) and the pistons have no thermal damage at all. I would expect your 12HT to be similarly resiliant.
I also have a VW tdi which has a factory temp sensor at the DPF entry. That has read over 800C. Also no problems.