After finally having finished the main campaign on Nightmare difficulty (for the most part) I can positively say that DOOM Eternal is an amazing game. This game is by far the best in the series in my opinion and I already feel like replaying the story. DOOM Eternal's gameplay is insanely good, very intense, high speed, stressful but the game does it in a really fun way. Even though it might be tough at times, I think it's really not that hard, you just need to be focused, have decent reflexes and know which buttons do what.
Now this games is also super lore rich, I personally didn't read all the lore pages all though I am planning on it, however I already know a lot of the lore from watching youtube.
Finally the main story is perfect. You truly feel like an absolute bad ass who won't let anybody tell them what to do and it also shows the immense power of the DOOM Slayer.
My plan now is to perhaps try an Ultra Nightmare run, get all the achievements and also play the ancient gods DLC.