While most AI is made on others' online servers even a decent gaming rig (eg 4090-5090) can do it 100% offline if you don't mind waiting a week while it does so (for rather long 15-20 second movie clips). Also there's still a number of countries that 100% legally don't care what you render, online or not, AI or not, photorealistic or not. If you are willing to pay to rent the computing power what you do with it is your own risk/responsibility as far as they are concerned (I imagine most P5 content is either made that way or offline on their own rigs). At least for now.