Yeah the first issue is in theory solvable, but they never managed to do it, not in a practical manner at least (huge cryocooled superconductors is probably not very practical)

The forces are from the immense magnetic fields, two parallel wires with current in opposite directions will repel eachother, so the rails are trying to move apart from eachother

This plus the heat causing material expansion plus the rails needing to be very straight for it all to work, and you end up having a bit of an engineering headache on your hands

But yeah it’s mainly when you build large ones meant to fire things at really really high speeds, maybe we’ll find a way to improve it one day, but for now it’s sadly dead in the water (in the military sector at least, but they tend to be the main driving force behind technology that fires things)