Gapps should be included in your flash queue when you did the update. Freeing your storage and flashing the gapps in twrp should fix it
I try different roms and with all roms have that problem.
I had the same problem on this one and PixysOS before that.
I used NikGApps instead of FlameGapps, but otherwise it was the same for me. Couldn't access the Play Store at all.
The thing that appears to have helped me with Google Play certification was installing Magisk and setting it to Hide.
Although I also flashed this PixelXL Coral ZIP before.
But if I remember correctly this didn't fix my problem.
All kernels are good ... the most important thing is the ramdisk optimizations !
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