I suggest you ask at AMD Forums Developers Server Gurus that deals with anything to do with EPYC processors: https://community.amd.com/t5/developers/ct-p/devgurus
Seems like AMD renamed AMD SERVER GURUS to EPYC Discussions under the AMD Forum's Developers.
Seems like the Maximum Operating Temperature is a company secret for the moment (-: .
I tried at several CPU websites including TechPowerUp and the only Thermal stat that is mentioned is that the EPYC processor has a Configurable TDP rating from 240 -300 Watts its Maximum Operating Temperature was "Unknown".
At CPU-Monkey (CPU Website) does seem to mention the Maximum Operating Temperature of 100c: https://www.cpu-monkey.com/en/cpu-amd_epyc_9534
NOTE: Not sure how reliable this information is since even CPU WORLD mentions the MOT is "Unknown"
EDIT: Better yet if no answer from the Forum open a AMD SUPPORT TICKET from here: https://www.amd.com/en/forms/contact-us/support.html