I'm currently looking for ma second electric guitar since the one i have right now, which is fender squire, has lot of limitations

I chose 3 guitars which are:
Ibanez RG870QMZ
Jackson Phil Demmel PDX

I usually play metal/punk rock

which one would be most suitable to get?
and I heard V shaped guitars are hard to practice especially when u r sitting down, is that true?
Have you played any of them? All guitars are different and you may spend a great deal of money on an instrument and find you just can't stand playing it. Your best bet is to go down to your local shop and play as many guitars as you can to find what really suits you. You may fall in love with one and decide you need to buy it as you're playing it. Because of this, we can't say "Pick that one." It just doesn't work that way.

It's also worth mentioning that your amp may be lacking since your main guitar right now is a Squier. So when you go down to the shop, try a lot of amps.

As for your last question, sitting down with a V is quite easy. You sit in the classical position and it becomes incredibly easy to reach across the entire neck.
Ibanez Prestige RG852MPB
Ibanez Prestige RG652KFX
Schecter Loomis NT
EVH 5150 III 50
PRS 212 DB
Line 6 POD HD500X
Deadhorse OD/Boss HM-2
definitely not the KH. it's a piece of crap with a big price tag...

I own the Ibanez, and I'm fairly happy with it. It plays great and the trem is actually pretty good (easy to keep in tune and quick to set-up as far as locking trems go). the stock pickups and tuners are brutal, but those are about the easiest things to change.

however, knowing your current rig, budget and willingness to go used will help alot.
Don't sweat the petty things and don't pet the sweaty things...
I would take the Ibanez, better guitar
Jackson DK2FS
Fernandes FR-65

Morley pro series pedal
BBE two time Delay
Empress Nebulus
Subdecay Quantum Quasar
Solid Gold FX Nitro

Blackstar HT stage 100
Marshal 1922 2x12 (V-30, Greenback)