No way your keeping up with detected objects so I expect you have many missed detections and ultimately your system is not working well
At 93ms your system can only check 10 frames max per second total. Even a single camera at 5fps is pushing your system limits. You can reduce frame rates to help this but ultimately you need more detection throughput
It looks like you are using CPU detection?
Before you start buying more hardware it might be worth trying using OpenVino to get your inference time down. It uses your CPUs integrated GPU for acceleration and can be quite effective. On my super low power CPU I get < 50ms, your iGPU is faster so you should get even better results.
I think around 10ms is the limit of the USB ones if I remember correctly. Only way to get lower is either a PCI-E one or go down a proper GPU route.
My Dual PCI-E Coral on a PCI-E splitter is around 6.3ms each. But unless you run a lot of cameras you won’t really gain anything.