I am using Android 7.0 Stock ROM on my Samsung Galaxy S6 (G9200) with a baseband version of G9200ZCS2ERC1 and security patch of ASKS v1.4 Release180122 SMR Mar-2018 Release 1. After I use Open Gapps 23 October 2018 ARM64 Android 7.0 pico in TWRP, I cannot login with Google Play or other Google apps if I use a network that bypasses GFW in China. If I use SSR or other VPN apps on my Samsung S6 to bypass the GFW, the Google Play Service would crash (and sometimes it would turn into black screen if I use multithreads in webview enabled in development options).
If I remove Open Gapps and use Go Google (a Chinese apps that installs Gapps for you), once it installs Google Services Framework, I would get repeated crashing modal popping up. I will need to pm uninstall gsf in adb. Same with installing Google Services Framework 7.0-3037786 from apkmirror or moving Gapps’ gsf from /system/priv-app to /system/app.
Typically I noticed all third party ROMs that I installed required to flash Gapps immediately after flashing the ROM or after doing a factory reset. I think it could be that I already installed a bunch of apps and used the phone for a while now without Gapps. I really would prefer to not backup everything and recover them after a factory reset.
It turns out that even if I do a factory reset and flash Open Gapps in TWRP it would still crash when Google Play Services is running as a result I can’t even get into the system because I would first need to log in once Google Play Services is installed before the system is initialized. Now I think this version of Stock ROM (G9200 for China) blocks Play Services or Services Framework. I will try to install some custom ROM during the weekend and see if I can get it to work.