What is the difference between a JV phone and a non-PTA phone?

A non-PTA phone

This only means the handset has not been registered with the PTA. The phone itself is fine and is not locked to anyone. A local SIM will not work until it is registered, but roaming data will.

A data-only eSIM works on one of these without any trouble.

A JV phone

JV means carrier-locked — the handset is tied to a foreign operator, typically an American or Japanese one. That restriction lives inside the phone and has nothing to do with the PTA.

No second SIM of any kind works on a locked handset — physical or eSIM, ours or anyone else's.

How to tell which you have

The simplest test is to put another physical SIM in it. If it finds a network, the phone is unlocked. If you get something like 'SIM not supported', it is locked.

Ask before buying second-hand. Sellers frequently use 'non-PTA' and 'JV' as though they mean the same thing, and they do not.

Does an eSIM work on a JV iPhone?

No. A JV iPhone only accepts the SIM of the carrier that locked it. No eSIM you can get in Pakistan — Jazz, Zong or a roaming one, eJurs included — works on it until the phone is unlocked.

Can a JV phone be unlocked?

Sometimes, but it depends on the handset and the carrier, and there is no guarantee. Until it is unlocked, an eSIM will not work on it.