I listen to primarily hardcore, punk and grind and my room is smaller than yours at 9x13. I’d recommend any room this small to load up on bass traps and at treat first reflections with anything you can afford. Bass bloat was a problem in my smaller room and after the $500 to fix it with bass traps the depth and detail of music really comes alive. Really, don’t skimp on this section. I made the same mistake as others and it’s definitely not the coolest or most fun upgrade, but the gains are worth it.
Speaker wise I ran Kef’s and was super happy with them. Detailed and fast. I guess it depends on the type of metal you listen to , but if it’s fast you want something that can keep up. I run focal now and am also really happy with the detail and speed. From personal experience you should be fine with any recommendations here. Good luck!