I have a Ryzen 3600 and RTX 2060 both set to not run in power saving modes which should obviously have no problem running this game, but when the action gets heavy, or even just certain times when there are a few explosions on screen, the game will dip below 60fps. Is this just the engine struggling under the weight of the content or is there something wrong?

Does this occur with both renderers for you?

The software renderer seems to have its own performance problems and looks worse.

Is the engine struggling. We talking about the Build engine here, yes it might be eduke32 but still is quite ancient. While my system is weaker than yours (AMD 570 and Ryzen 1600) it should handle this game like a champ but I also get some dips below 60 from time to time when to much stuff is going on the screen (especially when to many explosions)