Someone already beat you to it

https://hackaday.com/2023/02/21/youtube-as-infinite-file-sto...

I doubt it'd do anything to harm Google. Storage is dirt cheap and Google effectively has endless amounts of money and resources.

I'm not sure if "incompressible" is possible, at least in a way that Google would still consider an annoyance.

It's not, Google's encoding targets bitrate, not quality. If you upload incompressible content, all you get is forcibly compressed artifacts. Makes no difference to them if it's random noise or a high-effort video essay.

Easy to do with ffmpeg/mencoder.