Loved the first 2. Doom 3 was more Alien to the first 2's Aliens though, closer to horror/survival than the run and gun roots of the series.
Lots to like about Eternal for me, and lots to hate. It got a bit repetitive for me at times, massive arena fight then move on through some puzzles to the next massive arena fight. The puzzles were just annoying to me, rather than the old style Doom method of finding keys and switches to progress there were loads of jumping/platform style sections with really erratic mechanics (particularly the ones with the chain of circles to boost you the next platform in one level) so almost all of my extra life power ups were lost to repeated falls rather than combat.
Good array of weapons though, good level design, as always sterling work from Mick Gordon on the soundtrack (also did Doom 2016 and the recent Wolfenstein games among others) and some new twists on old enemies and bosses kept it mostly interesting. Might end up trying the Battlezone mode as well, purely because I don't have much else to do right now like everyone else.