Glad you asked -- it's a step forward for you to seek credible information when you don't understand how a process works.
The government is required to provide all
Brady material, which is defined as:
Evidence known to the prosecution that is favorable to a defendant's case and material to the issue of guilt or to punishment and that the prosecution is obligated to disclose to the defense : exculpatory evidence known to the prosecution that must be disclosed.
That doesn't mean that the government is required to know about or locate all evidence favorable to the defendant's case
that could possibly exist.
However, if they have it they must provide it. So, if the prosecution team didn't have the entirety of the video of QAnon guy, then there is no production requirement.
Also noteworthy; there is a deadline for provision of discovery materials and QAnon guy took a plea. If the discovery provision deadline hadn't passed yet and the guy took a plea with the assistance of competent counsel, then the plea will stand.
However, if the government had evidence favorable to defendant's case and did not provide it, the lawyer can file a motion to have the plea and the conviction appealed.
So there's your tell! The lawyer can spout off about how unfair life is on some cable talk show with impunity. The rubber hits the road if the lawyer appeals the plea and conviction. And to do so that lawyer will have to cite how the appropriate discovery process was violated. That happens all the time -- if you've got the goods it's a winner and there's unlimited resources to make it happen. And not just from right-wing sources; the ACLU will go to bat for him in a heartbeat if there's merit to it. but if it's bullshit a lawyer won't go into a courtroom with it.
My question is this: Will you actually read and attempt to understand what I just posted in an adult manner? Because if not, you will not get a measured, knowledgeable response on this topic again.