If it does boot up and if you get twrp going. After flashing twrp. Press cancel, swipe right to allow system modifications, hit wipe, hit format data next to advanced wipe button, type yes, reboot recovery, and you should hopefully be decrypted temporary, flash encryption disabler from zackptg5 here
https://zackptg5.com/android.php#disverfe then flash the latest magisk beta which is here
https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445 (you can use stable but I personally use beta so that's why I say use magisk beta), reboot system and hopefully congrats. You have successfully decrypted and root your Moto g7 play. And remember We are not responsible for bricked devices, thermonuclear war, ligma, or anything else so please keep that in mind before wanting to blame us lol the risks are laid out. And please if able send recovery logs and logcats as well as information on what went wrong so we can try to help Moto g family gotta stick together so we can help each other. MAKE BACKUPS OF STOCK BOOT AND STOCK RECOVERY because it's always good to be in that habit lol