* Once you've installed Android 10, your sim card will not work anymore if you go back to Android 9. To fix it, you must dump the Android 10 modem, and flash it to Pie.
* Twrp will break Android 10 if you mount the oem partition. Twrp also will not boot with the Android 10 vendor installed. I will work on this once official firmware is released.
Android 10 Raw Dump: xt1952-4 RETUS QPY30.71
Vendor, Oem, and System are raw images, so you will need to convert them to sparse images and install them with fastboot, or use dd commands to write everything to the correct inactive partitions. Do not complain to Motorola or me, if you brick your phone. This is a soak test, not official firmware. Information and the tools to convert the images can be found here.