EDIT: @mindbleach@sh.itjust.works shared something that might help to circumvent this shit:
Contained in these parentheses is a zero-width joiner: ()
Basically, add those to whatever you feel that might be filtered out, then remove the parentheses. The content inside the parentheses is invisible, but it screws with regex rules.
The exact rules of what links are banned varies from subreddit to subreddit. After posting a comment, I usually check in a private browser window to make sure it wasn't filtered.
you can also check if your shadowbanned/ incognito, if you look at any redditors profile. usually with typing in reddit dot com /user/[your account name]