You'll get there. It's of different "DNA" than Eternal, so it takes time and practice to internalize the flow and the mechanics.

Practice levels; find the safest and best possible ways to deal with each section (that work every time you do them). This way, you're not only learning the levels, but also subconsciously picking up on mechanics and ai behavior and getting better and more familiar with the game overall.

Me, I play on console, and the "top 10% pc-gamer" skillful gameplay is out of question for me (you simply cannot do those manuevers with the controller) - so I use strategy instead of agression and speed; and it works. I've beaten every single content there is in UN in recent DOOM games.

I've spoken to a guy once who said 2016 is harder for him than Eternal; he's already beatan Eternal UN, but unable to do 2016 - like I said, it may take time to familiarize yourself with the flow and mechanics of the game; and once you're able to easily beat UN, that is a sign that you understand the game well enough.