Sticky TCP sessions with IOT sensors

Can anyone help with the correct HA PROXY configuration for TCP IOT Sensors

Each IOT sensor has a sim card, and reports as IP:port
So most sensors look like they are on same IP but different port (when looking at netstat)

I need to be able to load balance, with sticky tcp session for each IOT sensor so its only creates 1 tcp session and continues to send its data (unless it gets disconnected), but based on IP/Port.

Everything I’ve seen refers to a cookie, but we cannot write cookies to IOT hardware.
I also need the balance mode to be least connections as to not overload one server.