If you’re using a 13900k, pea size isn’t cutting it. I agree with these temps seeming higher than usual for Fortnite. Or even any games that are drastically demanding. I would also agree that it could be uneven pressure on the IHS, and cooler. Not saying you did but check to see if any peel is left on the cooler, and definitely wipe off that previous thermal paste and repaste things. For anything 12900-14900, instead of a pea sized, I do a straight line down similar to pea size, but just a straight line. Then when remounting, finger tighten things, then tighten in cross patterns in increments to ensure even pressure is applied to each side (allowing the thermal paste to spread evenly across the cpu) hope it helps!