With Intel you can get away with very little thermal paste. The irony right now, is that Intel products usually run hotter than AMD. Especially since 10th Gen Intel CPUs push way more power vs their Ryzen counterparts (like RL said above).

Do AMD processors overheat?

No, in fact they are MUCH cooler than intel. Intel run insanely hot, because they are trying to push increadibly old technology to match modern performance.

Why does AMD run hotter than Intel?

The 3950X is hotter because it's 2x the number of cores and 4x the L3 cache. As others have said, it's also a much denser CPU - 16 cores and 64MB of L3 cache packed into roughly the same area as Intel's 8 cores and 16MB of L3 cache. Twice the performance in the same area = more heat.