I'm a really big fan of Faustcoven and the first two Varathron albums. Would really like recommendations for Black metal with a heavy doom influence. Heavy distortion and riffs. I know there are numerous, but it's easier to ask here for recommendations than browse all the bands on MA, individually.

Varathon, I don't know. But a band similar to Faustcoven, I can only point you to Cultic's High Command. It has the same raw, punk-ish doomy vibe. Not a fan myself, But I think it matches your request enough...
And then, Necros Christos?

Amen Corner's Jachol Ve Tehilá if you want something similar to early Varathron.