Since it is new, it is possible that the bolts holding the wheels in are loose. In the center of the wheels, there should be a screw or bolt that needs to be tightened. If there is no bolt visible, look closer, as there may be a cover to keep grass out. It is worth noting that I don’t have this exact model lawnmower, but most are pretty similar in design, so please take this with a grain of salt.
Have you tried cleaning the sim card with a soft cloth with isopropyl alcohol on it, and blowing out the slot with compressed air? Also make sure that the second sim card is inserted the right way, as if it is upside down or backwards, it won’t work.
I think I got it, but now the iPad is boot-looping. Any suggestions? Thanks. Edit: I just left the iPad sitting there for an hour or so, and it finally booted up. Thanks for the help!