Help with a problem

The game I play is not a solo mode, my game character has already reached the other world, but my NPC Ava has no currency exchange

Unsure what you mean. This sounds like a POE2 question?

The currency exchange NPC in POE1 is automatically available in town. I'm pretty sure he does not need any progress to unlock the currency exchange and it's only missing on SSF modes. It could be that a few upgrades are needed, I don't remember exactly. If it's not instantly available, it is certainly very early in the town progression.