Recently "Downgraded" to the new an improved XB8. Can I get my Old WORKING equipment back????

Have had nothing but trouble with this thing since it arrived. Comcast expected me to install it using cellular but I have no signal and rely on WiFi calling. They then went a step further and disabled my old equipment so I had to drive up to the store to contact them.  So this thing is finally running and has 6g, so what would prefer it just worked.  Constantly drops connection. (Can frequently see a popup on my screen saying internet connection has been restored) My printer will connect after resetting everything but only for a little while and then it cant be found again. Says offline....  Thought maybe signal was weak so I got an extender and set that up. Have 2.4ghz split from the 5ghz and 6ghz so pc, extender and printer all connect to the same ssid and 2.4ghz.  Have factory reset the XB8 and my printer and cleared all wifi on my PC.  Tired of jumping through hoops to try and get this stuff to connect for a few minutes.  Please send my old equipment that worked back to me!!!!   Thanks