Hello,
Because the delay of the gateway pinging the notebook is small, but the delay of pinging the mobile phone is large, it can be explained that the problem is related to the terminal.
If you are willing, it is recommended that you try to reverse the ping gateway from the mobile phone to do a test. Look at the delay of the uplink ping packet. The ping delay is relatively better, and the impact of terminal sleep will be smaller.
The power saving mode of the device will cut off the traffic flow path when there is no traffic, when the traffic needs to be transfered again, the path would be rebuilt, in which scenario the high latency occured.
Thanks