Third Party Multiplayer tower-defense with Photon PUN2

Hi there!
First of all, thanks for reading and trying to help you're an awesome person!

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I'm developing multiplayer tower-defense with Photon,
I wanted to know, what's the best way to instantiate the waves of enemies?.

I mean the players receive the exact same wave of enemies and I just want their health to update (and if they're being freezed/slowed/die).

How can I achieve that with the less amount of network power? I tried to instantiate within PhotonNetwork.Instantiate but the game becomes VERY laggy on both sides.

Should I call PhotonNetwork.InstantiateRoomObject to spawn the enemies? or what can I do?

Thanks again you're awesome!!,
Johny.