the thing about Ragna is that Jin really needs heat to stand a chance, the moment he gets 25 heat the matchup becomes easier... but in beggining Jin can't do much, 5C will get stuffed by just about anything with hit box (seriously 5C's hittable box is.... apparently Jin's cape is prehensile) and air game is risky with ID and 6A, so Jin just has to sit there and take it till he get's enough to use hirensou, which is his only reliable reversal in this matchup, 623C doesn't have enough horizontal range....
once gets on the offense it gets much easier, but getting there is the real problem with this matchup, Jin's just ill equipped to keep Ragna out.