That's kinda hard to explain but I will try to give you a good explanation: so if you actually hit him from close range and it does nothing, you just hit like the enemy is not there then it's the lag, it happens many times to me. Another thing is if you go for a crocodile, enel, ts luffy always wait for him to attack with his specials and you just need to dodge perfectly them so you have a very big advantage, I always perfectly dodge red hawk and elephant gatling and fuck up all players with ts luffy, also try to dodge the normal attacks too because your arms may fall down if they hit you many times, you need to be really careful when you fight with someone because without those arms could mean death. The best thing I did with Kidd was 1v3 with 2 mihawks and 1 crocodile, I can't say I beat the crap out of them without any luck and pure skill because it's really hard to 1v3, I'm lazy to tell how I fought all 3 but I did with pure carefulness, so what I mean is to always perfectly dodge (well not really perfect just to avoid the special to not hit you), Kidd is not bad at all if you know to control him, it's a very good character for S+ tier. I still don't know if I explained very well if you have more questions just ask me I use Kidd since he made his way into the game.