Is it possible to send scene results from one to another?

Question

Unity

There was a question about an online game, like TD. How to organize interaction between two clients?

My first idea was the Photon server. But then it dawned on me that I don't need to synchronize the actions of the players. The one who defends for the duration of the battle is just an observer. He does not have the ability to influence the battle, all his influence is curled from what he set up before the battle.
Thus, the scene of the defender is loaded to the attacker and he is already doing his business there ...

From this conclusion: all I need is for the second player to receive only the results of the actions of the first. Even with a delay of seconds ...

How can all this be implemented? (What are the options)

I think that to write down data about what happened 10 seconds ago and now and send it to the server. The 2nd user accesses the server and receives this data. Thus, the second is shown what happened on the stage of the first for the last 10 seconds.

But maybe there are already some ready-made options for this implementation? After all, in fact it is not even online, but simply observing what is happening on the stage of another.
Tell me how to do it better and what to use?