My Surface Duo 2 loses randomly ability to browse the web. Ping shows Internet connection interruptions... is it the phone or the net???

My Surface Duo 2 loses randomly ability to browse the web. The Edge or Firefox are unable to navigate and a ping test shows lots of errors appearing randomly. It can be after several hours without any issue, or stay wrong for long whiles. Both browsers fail exactly the same and they don't interfere one the other, it happens the same if you close one of them.

Latency uses to be too high even when it is working OK, and for instance a 64byte ping round delay is about 30-60ms in 5G depending on coverage quality (which still seems to be a lot slow for NR-NSA!) and not much more in 4G (40-80ms). In fact latency in 5G is hardly distingushable from 4G. My Surface Go LTE pings last about 3ms in the best case and up to 30ms in 4G, so the Duo 2 is really slow even when its Internet does not crack. But when it does, it stays many minutes with random behavour and a lot of errors, ping lasting to to 300ms or more or just not reaching, or, when browsing, simple unable to reach the target website.

The Surface with LTE with me checked repatedly does not give any error in the same locations and moments.

I tried by changing several adjustments without any result:

• not to use 5G. The prob is the same in 4G.
• Change the APN protocol from IPv4/IPv6 auto to IPv4 only. No result.
• Change private DNS from "No" to auto". No result.

The only thing that works normally (but not always) is to switch the phone off and on. Just to add, the problem happens also more after moving from a place to other, outdoor to indoor or vv, but also not always.

I am not sure if the cuts are for the complete Internet connectivity or only to reach IP addresses / DNS's. I know only from the browsing and the ping.

I called to the support and somebody asked me to return the device. This is very disturbing for me as I use the phone continuously and I have installed my work apps. I think there should be some SW adjustment or restoring tat could be tried.

I have the phone since november and the problem is more or less since the beginning but I think that it happens more and more often as times passes.

In january I installed to the phone the Slim Pen Cover which covers the front face and allows to charge the pen magnetically or via NFC or both (I am not sure). I wonder if this is penalizing the antennas coverage / performance.

Celular network adjustments

Preferred type 5G (or any other, the problem remains the same)

Adjustment version 21407-113594371.113594371 (I ignore what is this)

Used net 5G NR NSA

SIM data (SIM 1):

Signal level typ -90...-85dBm 50..52 asu (up to -60 at times in 4G/3G(

Phone data:

Microsoft Surface Duo 2

HW version MP retail (12)

Touch Version 26.302.139

Compilation data 2021.1116.111

SO data:

Android 11 updated Jan 1 2022

APN

private DNS no (or auto, the problem remains the same)