I use my bass amp for guitar practice at home, because I'm primarily a bass player and it works well enough. I'm currently using a Harley Benton Drop Kick for distortion plus a 7-band EQ which gets me a decent enough sound, but I'm looking for more variety. Especially something high gainy for a modern-ish metal riff tone. My current setup is unsurprisingly pretty good at stoner/desert rock stuff, though the amp is not nearly as dark as you'd think.

My guitar is a Yamaha Pacifica with a bridge humbucker, currently tuned to C standard, amp is a Fender Rumble 25, older version.

Anyone have an idea what would work well here? Maybe a Boss MT-2 or clone thereof? I read it's decent if you use the effects loop to skip the amp's preamp section (my amp does have an effects loop), but I'm not quite sure if it's the right pick for the kind of unconventional setup I have, or if it would even be a good choice for modern metal tone even if I did use a guitar amp. I'm trying to keep the budget reasonable, btw, so please no boutique pedals.

I could get a proper guitar amp, but space is a bit limited here and bedroom-sized combos don't usually do a great high gain sound on their own, anyway.