Hey Brevity,
This may or may not be the answer you're looking for but, from my experience, it's the right answer.
Don't think of links in terms of good and bad quality. Whilst there certainly is a difference between a good and a bad link, the first thing you should be looking at is the link profiles of your biggest competitors in the same niche / vertical.
A good way to find these sites is with SEMrush if you don't know them already.
Look at the kind of links your competitors are getting and how the page / domain authority of these links is distributed in their link profile. Eg 90% of their links are on pages with 0-10 page authority, 5% 10-20 page authority 5% over 20.
Now, from my experience, Google doesn't have a model of a "good" link profile, only what's standard in that niche. If everyone else is buying shitty comment spam then you have to do that too. Fight fire with fire. On top of this you optimise the balls off your site and build up more of these high quality links ON TOP of the other links.
I certainly wouldn't just turn off a Linkbuilding method that has already proven it works for your site.
Once this starts getting results slowly wean them off this spam. Think of it like gradually cutting off a smack addict's heroin supply, haha. Obviously comment spam isn't something you want to rely on forever, but its too late now if the ball's already in motion. You just have to slow that baby down first.