Here are some steps you can try to troubleshoot the hardware issues you're facing with your Motorola Moto G 5G Plus:
# Power button: If your power button is not working, try a soft reset by holding down the volume down button and the power button until the device vibrates. If this doesn't work, try connecting your device to a power source and holding down the volume down button for 10-15 seconds.
# Touchscreen: If your touchscreen is unstable, try a soft reset or restarting the device. If this doesn't resolve the issue, you may need to perform a factory reset or take the device to a professional for repair.
If you are unable to resolve the issue on your own, I would suggest contacting the manufacturer or a licensed repair service for assistance. If you are not confident doing any of this I would suggest going strait to a shop. Best of luck!