All of the options above are possibilities. We use a Roku (similar to Fire Stick) for the same purpose. Essentially, our camper TV is no different than our home TV. We use Rokus at home as well, and do all our watching through streaming services, so there is no difference except for the wifi source.
Since we are periodic trip/weekenders, we can manage wifi through a cell-phone hotspot, but we do usually have some stuff downloaded from Amazon, Netflix, etc. in case the signal is bad and we have crummy weather that traps us inside. We download this stuff onto a laptop that we can connect via HDMI if needed.