Snapped needles are the most likely thing that could happen.

Sometimes people assist the motor by turning the hand wheel, and I’ve heard that can bend the frame of the sewing machine in some cases. That’d be the most catastrophic failure potential I think

You can try a heavy duty needle, but there’s a pretty good chance a domestic sewing machine just won’t work with seatbelt webbing. I’d recommend caution

Hey OP, I’m on a similar journey (except I’m using an rpi kubernetes cluster)

I don’t have advice but I do want to wish you good luck