Just began my life as a melee bot...

and so far I'm sucking at it (dramatic pause) I'm currently using ZSG+Kamui Staff but I can't melee properly I either pass through enemies or sometimes out of nowhere (another dramatic pause) so will you guys help me how to melee properly so I can finally enjoy what my RT's worth?

I never used ZSG, so I wouldn't know.
But when I'm using Jikun or Byne, I usually targets large arts or mobs.
Passing through the enemy when meleeing is normal, you have to get used to turning the camera quickly to face the enemy when that happens. So that the next combo will go back to your enemy instead of you getting more far away. Kamui staff already has quite big range, so you shouldn't have that much difficulty in targeting.

Once you took care of your targeting, you'll have easier time hitting opponents. Just don't be too spam happy with combos and know when to stop.

The thing is you're focusing too much on maximizing your melee range. It's effective with some weapons but it don't go TOO far without proper practice.

If you want a starter recommendation, use a Beam Sword or Sonic Blade. They both have a high rate of stunning other LND bots in case you get locked into a melee fight.

Utilize Zero Step to make up for Beam Sword's poor movement range, it also boosts your damage which in turn gives a higher chance to stun the enemy. It helps.

(I'd write more but ima head home, just released from school lol)