Here are a couple of good, fact based videos on the proposed ban or perhaps more accurately re-classification of pistol braces from a commonly sold firearm component and into a NFA item requiring special, additional, after-the-fact permission to continue owning a product you already legally purchased.
Something that came up in both videos and elsewhere is that Trump is completely oblivious here. He could stamp this out but he is too busy doing....well, I don't know what the hell he is doing but he certainly isn't using the last month of his presidency anymore efficiently and effectively than the prior 47 months. He might be on our side but generally other than rhetoric hasn't done shit for his most loyal voters.
This is a coordinated effort being driven by the impending Biden administration and is just the beginning.