I dunno, man, if Hoult gave more or less the exact performance he gives in The Great as Luthor it wouldn't be comic book Luthor but it would still probably be the highlight of the movie simply because he's an electric, hilarious performer with the right material. He hasn't been terribly compelling in leading man roles in large part because those movies have been, generally, boring and terrible. The only member of the primary cast who has done work par with Hoult at his best is Brosnahan. Which isn't even a slight really, Corenswet's career has barely started and I don't think he's had a role yet that showed him off particularly well (I know a lot of people love him in Hollywood but that honestly is part of what made me become the sad, lonely soul alone in the CBM fandom universe turned off by his casting) so he could very well have similarly great work in his future and Gisondo just isn't the same kind of actor at all.
He absolutely has had standout roles. Obviously Skins is a big one, I think he's really moving in Fury Road, True History of the Kelley Gang is the peak of his maniacal, unhinged shtick (also the best example I can give of him being threatening) and The Great is of course his career highlight. I don't think he's the greatest actor of his generation, I'm not the president of the Nicholas Hoult fan club, I just find the attitudes towards him in CBM fandom incredibly weird. The ways his performance could go "terribly wrong", imo, are a lot more exciting than seeing someone just do DCAU Luthor. I'm not that interested in "classic" anything in CBMs anymore.