We have a C2 at home, and I clamp this on it. Works great if your gym will allow you to use it (or if there's something else nearby to clamp it onto).
https://www.amazon.com/Gooseneck-Bed-Phone-Holder-Mount/dp/B07S9JXQP2?ref_=ast_sto_dp
These things are great in general. I have three of them in our basement to hold an iPad for AF+ - one each on rower, treadmill, and overhead joist for floor stuff.
There's an android app called VarsVR player that would let you watch downloaded movies.
It worked with VR videos, but could also handle static movies and 3d movies like Avatar.
That said, just get something like this: https://www.amazon.com/Gooseneck-Bed-Phone-Holder-Mount/dp/B07S9JXQP2/ref=sr_1_1_sspa