Doom 3 hate/praise comes in waves. Overall, its generally well liked. Back when I was in college, it was common for people to call it "the best Doom". Public opinion shifted when Doom 2016 was a return to form for the franchise. However Doom Eternal was so polarizing (I personally think it's not only the best Doom game, but the best FPS game ever made, and probably the best video game period ever made), that support for Doom 3 is back really high, because a lot of people got filtered by Doom Eternal, and think Doom is a horror franchise for some reason.
You should try Warcraft 1. It is primitive by today's standards, but once you get used to it, it's so good. I've never played another RTS where unit positioning matters so much. You can completely turn a battle simply by controllying a bridge with archers and catapaults. It's deep for the time.
I actually dont think Malenia was that hard. Maybe it's because I was playing a magic build, but once you got used to her attacks, she's definitely managable. I died against her a few times, but I don't even think she's the hardest boss in Elden Ring. Orphan Of Kos in Bloodborne, in my opinion, is the hardest FromSoft boss. You really need to memorize his attacks to beat him. Slave Knight Gael in Dark Souls 3, I also found harder, but I also think he is the best boss fighy FromSoft ever designed.
On an unrelated noted, the hardest boss from any game ever is Sigrun, the final Valkyrie, in God Of War 2018 on Give Me God Of War. It was painfully apparent that game was never tested on that difficulty. I died probably 200 times before I finally beat her. And the rewards weren't even worth it.
I think you just don't like RTS games, because Warcraft 3 and StarCraft are definitely the top of the top in the genre. You can dislike the addition of heroes, but to say they make the game DOTA is simply false. A hero, even a high leveled hero with farmed items, will still die to a well strategized army. The only things the heros did was add a slight RPG mechanic to the strategy.