I have also had experiences with my RAM reaching 80+ C when running some programs.
Hopefully, this is within operating temperatures and does not reduce the longevity of the modules. The RAM chips are rated for a maximum temperature of 105C but that definitely shouldn’t be the target range.
Unfortunately, there doesn’t seem to be a great way to add cooling to the modules so they do not become so hot. Maybe adding thermal pads to make contact with the midplate would help, but they would have to be quite thick to reach.