I also technically never beat Doom 2 as I just stopped playing it after reaching map30 and went to play btsx instead and I don't think I ever will lol. I know everyone dislikes most of the maps on doom 2 for very good reasons but genuinely that iwad bores me out the second I enter underhalls. Its ugly, repetitive and when it isn't super easy its annoying, the Icon is just a culmination of that. Its not hard, its just annoying and I'd rather not waste my time on it ever again, my inner completionist can go throat a cactus
I have literally 0 patience for secret hunting so if I cant find them mid playthrough I just go to the wiki. This probably isn't that bad but I still feel the need to point it out
On my first playthrough of Doom it took me ~10 attempts to beat City of Dis and I had to google how to kill the mastermind. I was playing single segment. Other maps that I sucked at in this fashion are Doom 2's Factory and Spirit World