Devices Auto Switching to Xfinitywifi

I am having an issue where my devices prefer and automatically switch from my network to the Xfinitywifi network, which I believe is the guest network. This can be frustrating because 1) I cannot print because my printer is now on a different WiFi network and 2) I’m concerned with security as the guest network does not have the same security as my primary network and I don’t have any way of knowing my device switched over unless I manually check WiFi settings. Is there a way to prevent the auto switching or should I just turn the guest network off? I rent my gateway from Xfinity and have the 6e model that came out recently.