FIFA claimed the 2022 World Cup final reached 1.5 billion people worldwide, but again that seems like it was mostly via broadcast television and cable.
As far as single stream, Disney's Hotstar claimed 59 million for last year's Cricket World Cup, and as far as the YT platform, the Chandrayaan-3 lunar landing hit 8 million.
100 million is a lot of streams, let alone 300. But also note that not every stream reaches a single individual.
And, as far as the 59 million concurrent streams in India, the bitrate was probably very low (I'd wager no more than 720p on average, possibly even 480p in many cases). It's again a very different problem across the board due to regional differences (such as spread of devices, quality of network, even behavioral differences).
