I’m personally using the SanDisk card below. It was recommended on a robotics site. I think you should search for “Jetson SDCard recommendation” on Google and see what comes up. I don’t know too much about SDCards, but I believe the speed of the card matters with the Jetson.
I read on the NVIDIA developer forums that it is better to use an SSD when saving video to file. However, I do not have experience with this. I suggest you try posting a question to the NVIDIA forum before you spend money on the SSD.
If you post, and if you have time, link back to this discussion thread in case other people want to experiment with the RICOH THETA.
Your Jetson Nano is acting differently from mine. Are you running JetPack 4.4 from the NVIDIA site?