How modern? Because there's lots of artist from the late XXth who had interesting and recognizable styles that are hard to replicate, both in style and vibe. Moebius (Jean Giraud) comes to mind. It is deceptively simple, but to replicate it you need to have a solid grasp on character design, stipple shading and crosshatching, color theory, and composition. It's not traditional comic-book style, and you cannot approach it with that mindset and expect a good outcome.

Current artists, I suppose the artists behind Valorant's art? There's a lot of decision making when it comes to how much detail to include, since its very stylized. But I'd argue it's not as hard a style to replicate as Moebius'. Bartosz Kosowski also comes to mind. He's really, really good at depicting things in his style, and you'd need a solid grasp at anatomy and faces to replicate it.

Vantablack?