After flashing, mount system from TWRP, go to the "Advanced" tab, click on Terminal and type the following command:
echo "ro.setupwizard.mode=DISABLED" >> /system/build.prop
This did the job for me, since it appears that there is a problem with the Setup Wizard on arm64 gapps.[/
Hello, sorry for my ignorance, what are the next steps to put the command ??? I'm a clumsy, please can you tell me step by step? My moto g4 plus xt1642 2 gb ram
Well, after you flash your desired ROM and gapps, go to the main TWRP menu, click on "Mount" and check the "system" option. Make sure that "Mount system read-only" is NOT checked. After that, go to the main menu, go to "Advanced" and tap on "Terminal". Type the command, tap on enter (on the keyboard obviously), go to the main menu, go to "Reboot" and tap on "System". Done. Now you wait for the system to boot, will usually take a max of 8-10 minutes (for the first boot).
What the command specifically does is that it disables the Setup Wizard that you see when you boot your phone for the first time, because it causes boot loops with OpenGapps 8.1. After that, you can just go to "Settings" and you will most probably be greeted with the "Finish setup" option (Or "Finish setting up your Pixel" option) that essentially does the exact same thing as the Setup Wizard would do.