There's Daniel Ingram's stuff, I liked his book and there's a forum at https://www.dharmaoverground.org/ , haven't checked out how cranky it is.

Culadasa's The Mind Illuminated is detailed, non-mystical and seems to have a solid following with an active /r/TheMindIlluminated subreddit. /r/streamentry subreddit seems to also be pretty focused.

Rob Burbea and Shinzen Young have also written a bunch of non-vague, non-mystical stuff and seem to be well regarded.