I think for the most part, a lot of these Youtubers would either struggle to upload or make content (Especially true if their city of living becomes a frontline)
Thats also not taking into consideration the possibility of a lot of them being conscripted or even volunteering. You would likely see an actual drain in terms of content on there because Most would be packing up and hauling ass out of America OR being put into the previous situation i mentioned.
You would absolutely have guys similar to Youtubers like "CivDiv" uploading combat footage etc.. and showing how the fighting is on the ground. Not to mention the most fucked thing being that if a E-Celebrity does serve and is KIA'ed then you would not only hear about it, but possibly see it as well. People are happy to record anything these days.
Essentially, the Platform would probably wind up being drained of content for a while or flooded with Combat footage, becoming a new Liveleak.