Well in false confession, the guy isn’t necessarily a bad guy per se but he’s really scary.
im unsure if this is the type you're looking for (sorry if its not!)
http://www.mangago.zone/read-manga/hoshi_to_harinezumi/
http://www.mangago.zone/read-manga/goriyou_wa_keikakutekini/
http://www.mangago.zone/read-manga/danshi_koukouseiteki_kazoku_keikaku/
http://www.mangago.zone/read-manga/shiba_kun_to_shepherd_san/
http://www.mangago.zone/read-manga/nirameba_koi/
http://www.mangago.zone/read-manga/rutta_to_kodama/
i feel like honto yajuu will also fit what you're looking for, but its popular so i kinda assume everyone has read it ^^ just in case tho
http://www.mangago.zone/read-manga/honto_yajuu/
does it have to be bl? because this one http://www.mangago.zone/read-manga/uncle_cool/ is really interesting and i recommend it.
Do you have a story where the bad guy is actually a sweetheart?
Or where someone looks scary, but is actually really kind?