Thanks for reaching out. I'm sorry to hear that you're having an issue with the connection of your Canon MG 3620. I'd love to know more about this and I have a few questions:
Looking forward to your response.
Thanks for the added information. If your printer is not showing up on the mesh network, it's possible that it's not connected to your Google WiFi network. You could try resetting its network settings and try reconnecting it. Please make sure that you select your Google WiFi network's name during setup.
Let us know how it goes.