OREI SplitExtend HDMI Splitter Extended Display for Quad Monitor - Laptop Multiple Monitor Adapter with 4 Displays - USB-C to HDMI Adapter, 2X 4K@30Hz & 2X 1080p - Drivers Required - Windows/Mac

https://www.amazon.com/OREI-SplitExtend-Splitter-Extended-Display/dp/B0DG9PZDYL This adapter splits a single 4K signal onto 4 1080p monitors, read comments folks are using with old airs that were limited to one display