could a shikigami perchance create an a domain like the finger-bearer?

hypothetically if a shikigami could do barrier techniques, could they actually manifest a barrier? it wouldn’t have a sure hit of course but could they do it like the finger bearers?

another question can shikigami do hand signs to boost their users output potentially?

what kinda jujutsu CAN shikigami do to help their user, besides rct output which rika showed