When mixing metal, it's crucial to have monitors that can handle the complexity and power of the sound. Based on your needs, the Yamaha HS series, particularly the HS8 model, is often recommended for its clarity in mids and highs as well as its impressive bass response. They're known for their flat frequency response, which helps in accurate mixing, even in less-than-ideal acoustic environments.
Another solid choice could be the KRK Rokit G4 series. These monitors are famous for their punchy bass and are well-suited for metal's dynamic range. They also come with an integrated room correction feature, which can be beneficial if your room isn’t fully treated.
If you're open to investing a bit more, the Adam Audio A7X monitors provide excellent detail across all frequencies and are highly regarded in the metal music production community for their clear highs and articulate bass.
It's always a good idea to test a few models in your space if possible because room acoustics play a significant role in how monitors perform. Additionally, consider using some bass traps and diffusers to optimize your current space—it can make a noticeable difference.