This is still the divide between FPS back then versus now...

In DOOM 2016 and Eternal, I feel like the game gives you highs and lows. When you reach a monster arena area, the music cranks up and there's shit flying at you from all directions. Death can come quickly. It can be very intense. Then you know when you killed the last monster because the music dies down. Now you find a door or whatever and you're on the next linear path to the next monster arena. Now this linear path feels super boring because there's no monsters or music. There's some platforming, which can be fun. But it's like the arena area was so intense, then they just pull that carpet out from under you and it feels borderline boring.
In the original DOOM games, I mean, I'm sure we all know how they play. But specifically, in contrast to 2016 and Eternal, you don't really have these highs and lows. Sure, there might be some small areas where there's no monsters. But in the original games, you know that monsters can pop out at any time. Or that there's traps and hidden triggers. So you don't have any highs and lows like you do in 2016 and Eternal. You're always at the high, because you're always kinda on edge not knowing what might happen (assuming you don't know the game forwards and backwards like some of us do). And the combat isn't confined to these specific arena type areas, it's spread out all over a huge non-linear map. You can clear all monsters from a map, or intentionally skip the ones you know you don't have to encounter.
So to sum it up, I guess what I'm saying is this: The original DOOM games, the combat feels more organic. In 2016 and Eternal, it feels more like an arena combat game with hallways connecting one arena to the next.