When I was a regular Zwifter (laptop, Garmin Vector Pedals, Lemond Revmaster Spin Bike), I would use my pretty heavy duty music stand which worked quite well. Price in the $50 to $75 range at most music outlet places online or even brick and mortar. You need the heavy duty ones that tilt way back. This setup was very stable.
dave
ps. You will notice my other avocation in the pic
