Manny_S Hello and thank you for giving us this examples. And this will be some video! Looking forward to see this!
Unfortunately I guess I'm not going to see this scene with the high bitrate as you already dont put those one available in the new slr videos (some say its behind a paywall of the paypervideo... i will never pay that much for a video).
The difference is noticeable mostly how @petex67 says. When the person starts to move you can notice blurriness and out of focus on the smaller files. While on the larger files is very crispy and image flows a lot better. Its not a question of AV1 or H265, its a question of bitrate. 30 mb is just too old image.
But dont get me wrong, 120mb bitrate is very good bu also too much I think. But in the middle term of this I guess it would make everyone happy (or at least most people). But as I said, for me 30mb bitrate is just not good quality to see.
Thank you for all your work.