Push notifications work in one sing-box app and doesn't work in another, while settings are the same

VPN
1

Hello,
I live in China, so use VPN 99% of the time, I use a sign-box subscription with multiple VMESS & VLESS nodes.

I tried multiple apps, and some of them I working (subjectively) more stable than the other apps with the same subscription, but I don’t get Push notifications with them.
For instance, There is an app called Surboard, it’s working perfectly fine, except for notifications:
I have tried:

  1. Changing lots of general settings in the app (like Allow LAN etc)
  2. Spit tunneling apps (including system)
  3. Disabling the battery optimizations for both: VPN app & affected apps

The only thing that seems to resolve the issue is whitelisting:

  • Google Play Services app
  • Google Services Framework

But once I do this it weather widget and live translation stops working.

But it makes no sense for me, because once I switch to the least stable app Push notifications are working while Google Play Services and Google Services Framework are not whitelisted.

Did anyone face this issue or have any suggestions?