If you’re trying to say that a recording of a video game is not considered fair use under copyright law, then I give you the existence of Youtube and Twitch as counter evidence.

So, funny you should say that…

This happened to Persona 5. Atlus felt that they had a legal basis to make copyright claims on the game - in their case, circumstantially around spoilers (I guess because they wanted people to pay $50 to experience the late-game story)

And they walked back, not because lawyers were dismantling their case, but because of public outcry. That basis of public preference is what has encouraged game studios to be friendly with Twitch / YouTube, not because judges would rubber-stamp any fair use “transformative work” argument. That is also why many games have given explicit notices to say “Content notice: Please feel free to share videos of this game wherever you’d like!” etc - as it is a non-default judgment.

So, as strange as it is to say, most uploaded videos of a game is in some murky legal territory. Obviously, most studios don’t care and even prefer them to be shared for visibility - or took the time to include those notices to make it 100% legal. But when the recording came from an internal build, the game itself is “stolen”, in that the person playing it breached either terms of viewing or terms of employment, and then the person re-uploading it is breaching copyright as they had no permission.

If you want to work it through the other way, permission to upload a work is non-default. You need to provide a basis it’s legal, not a basis it’s illegal. In many cases, it’s “I made this”. For 99.9% of video game content, it’s “the developer is okay with it”.