Issues When Using Google Mesh to Extend Signal

I have been very happy with the T-Mobile 5G home internet service at my house.  I get excellent signal if the gateway is in an upstairs window.  I bought a WIFI 6e adapter for my computer and can consistently get over 300mbs download speed.  However, the WIFI signal does not reach my entire house.  I tried a Netgear extender and could not get it to talk to the gateway.  It was recommended by a T-Mobile rep to get the Google Nest mesh system and t-Mobile provided me with a discount for it.  However, I have been struggling with it being a sub-network to my home network.  I need to connect my PC to it in order to connect to my printer and other devices on my home network but the download speed is slower on my PC when connected to the Google mesh system 200 vs 300 mbps.  Also my smart TV needs to connect to the Google mesh system due to its distance from the gateway and when streaming the video occasionally stops for a second or two even though the sound does not.  I would keep my computer connected directly to the gateway but need to use the printer which my wife also uses and she must connect to the mesh due to the distance.  I've tried opening the ports on the Google router but still cannot see my printer when connected directly to the Gateway.  I'm open to any solutions to this but t-Mobile needs to come up with it's own mesh system so we are not having to deal with sub-networks.