You are trying to install TWRP ?
Be careful, your device is a Moto G7 Play (channel) and not a Moto G7 (river) (according to what you said).
There is an unofficial build for your device here.
So you are probably trying to install a wrong version of TWRP which is why it fails. There is a TWRP for channel here but no idea where it comes from or if it works, at your own risk.