It’s possible to track the number of hops that a device on a network has, since TTL will be 8-bit numbers (and ususally start at 64, 128, etc.) if the TTL of a packet has 64 from the main device, the devices it’s sharing with will be 63 (and so on un the chain for N+1 hops). This may not be exactly how they do it since device fingerprinting would be way simpler, but it is a plausible way of tracking that a device is using a hotspot.
Yeah ps4 works a charm, the hard part for me was figuring out why an Xbox controller didn’t. Turns out some of the older models had deprecated Bluetooth that it couldn’t connect to, so went with a ps4 one instead.