They don't and you can easily verify it by using "Takeout" feature. At least if they try to obey GDPR.... And there is a lot of interesting data in the export.

It depends on the interpretation. Google could have easily claimed "we'll preserve anything related to the investigation", but without explicit list, it says nothing. Google has possibly informed affected employees to adjust settings once something related to the investigation comes up. Many work-related chat conversations likely contain trade secrets and it wouldn't be beneficial to Google to effectively publish them as a part of a public hearing. In the end, no one has requested them. Should they be required to capture also this part?

It's more about complexity than about latency. Like: a hidden opponent triggers something, that affects area I see. Games have 3D sound, so I should know the direction. Programmers may compute visibility, area of effect and all directions of all clients on the server. That's complex, computationally expensive and has to be upgraded with client once some inputs change - it's easier to send the enemy's coordinates. That said, it often can be done better.