Another holistic question/approach:
Is there any way where all changes that happen in the layout are updated automatically at every 0.2 seconds.
Like I wrote earlier, the only changes that could happen are positions of sprite instances, text changes (score) and opacity changes.
Maybe I am too stuck on the idea that after every action a message has to be reporting everything about the actor that had undergone interaction/change, and there could be a way where all positions, angles etc. is mass processed the whole time?
That would be a terrible approach. Never ever mass send messages for everything to everyone all the time.
The best practice for multiplayer games is the opposite, send as few messages as possible.
Read more on the photon forum or general multiplayer web pages for best practice.
(Lerp the positions from the position data in the messages instead, after an update.)