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.
It’s just like adarza said.
Left: logged in. My own activity is shown.
Center: logged out, old reddit. It claims that the user doesn’t exist.
Right: logged out, new reddit. It claims that the user was suspended.