You won't see curvature when you just look straight forward at the horizon. The only evidence of curvature in that footage is the fact that you can see further and further the higher you get. If you want to see curvature "to the sides", you'll need to look down at the Earth to get some form of angle.
A student team in Norway sent a balloon to the same altitude and took this footage
https://www.facebook.com/kogstarburst/videos/1496581273718019/
There you can clearly see the curve :)
But it doesn't matter. We already have plenty of images where you can see curvature. Like this one taken by SpaceX
How do you determine if it is CGI?
First of all, that's not a very clever way of determining if something is CGI, you are susceptible to your own human errors.
SpaceX have placed cameras at two places on their launch vehicles. One is attached to the main body of the Booster (First and lower stage of the rocket) pointing downwards, the second place is inside with the payload and the second stage engine.
Please tell me how any of this is faked.
Except, I just told you that we are monitoring them and maintaining a communications link with our ground stations as they fly. But you just chose to ignore that because you can't explain it away.
You're just asserting what you are asked to prove and doing circular arguments. Claiming space is fake, and then denying evidence that contradicts it by asserting that space is fake.
You're making no sense.
I have a question for you, gravity. It pulls stuff together in a spherical manner, anything for e.g a flat earth would be immediately crushed into a sphere which we all know that it isn't except for you. So could you explain how it works on a flat earth?
Your prove in the video 6:11, the entire concept of flat earthian gravity relies on bouyancy and the relative density of objects in the medium. By your definition of gravity IT SHOULD NOT WORK and I repeat SHOULD NOT WORK under a vacuum, but jokes on you it does and therefore gravity cannot be a hoax. Here is just a short demonstration :)
You don't know that for sure. You're kidding yourself if you say so. Even if it was proven tomorrow that indeed every single NASA video had been faked (for which there still is no evidence) it would do nothing to change the observable fact that we live on a round planet. Something we have known for more than 1000 years before NASA existed.
Calling gravity "a hoax" is just hilarious. Again, even in the Napoleon wars, they used models based on gravity to aim their cannons and understand how the cannon balls would fly and where they would land. You may want to look into the works of Pierre-Simon Laplace if you want to learn more. (I highly recommend his work) But whenever we build buildings, send missiles, do experiments or fly planes based on models that assumes gravity to exist it works.
You do know that it is basically the same altitude as the video you linked above? Right?...