I have a 3900XT, so a step down from you. My other components are; an X570 and H115i AIO, with a 2080S, in a Corsair 680x case.
I've just tested on Prime95 and my max temp was 78°C, with an average of 76°C and an average clock across all cores of 4215Mhz, and showed 87% average usage.
I also ran the BMW and Classroom render on Blender, 56 and 163 seconds respectively - max temp 67°C.
I don't see any issues with mine and I'm not sure how or why I'd want my temps and/or performance to be any different.
Now that's the sort of figures I would expect to see.
Do you recall the setting you had the H115i on?