[firmgently]

This probably refers to TTL, which can be easily changed to disguise the 'hop' from your device to your phone... but Deep Packet Inspection is apparently commonly used nowadays too. To get around that you need to be encrypting with a VPN or similar setup.

This is my simplistic understanding of the state of play based on the last time I looked into it but as mentioned above it's easy to Google.

[dzhiurgis]

How do you fix the TTL trick?

[joecool1029]

on the AP (phone):

iptables -t nat -A POSTROUTING -j TTL --ttl-set 65

You will need TTL target built into the kernel of the ROM you are using. LineageOS is unwilling to do it officially, so I build my own with it enabled.

It's a good idea to only use ipv4 when doing this. A few services are detected on TMUS, so for those VPN. Sprint doesn't seem to care, but they have a patent on TTL detection too from around 10 years ago. I normally do not VPN, but I do use my own DNS since I don't like carrier hijacking.

[gsich]

You set the default TTL in your OS to +=1.