I wonder if there's some sort of GSM hotspot device where it connects to 4G/5G networks, but creates a small localised 2G/3G cell for older phones. Kind of like

I wonder if there's some sort of GSM hotspot device where it connects to 4G/5G networks, but creates a small localised 2G/3G cell for older phones. Kind of like how we have mobile hotspot devices, but instead of (or addition to) creating a WiF hotspot, they provide 2G/3G...