[Photon server] How to photon server spawning enemies

Hello. I am using photon server and I am not sure how to spawn monsters and synchronize them across all clients. Each monster has their own AI so they can move.
I am thinking of giving a client the owner and spawn the monster. When the monster moves, this customer sends all of the monster's locations to another customer. But the problem is that this main client will have to send a lot when the monster moves, and when lag all other clients won't get the monster's location anymore.
In my case there are multiple zones, each containing many moving monsters.
i hope someone will give me a good idea to solve this problem

Yes, you are on the right track. And yes, when there is lag on the client that controls the AI, others will get updates later. This is sadly a trade off for not running a server to avoid this.
You could come up with a scheme to distribute control of monsters but if you don't send updates for monsters that are not "active" and if each update isn't a lot of data, some player will be able to send this just fine.
We usually make the Master Client run the AI. It's a convenient convention to assign who is doing the job. You should make sure that there is a transition of AI control, when that player drops. To make this possible, you might want to send a little extra info to everyone else for the AI control.

The client server will have to assume many roles. when it is lagging, it will not be able to send location to other machines. In Pun, it has a very convenient photonView