Issue with Arris G36 with Xfinity 10G upgrade system since 7/2023 with all Intermittent, connectivty, performace speed

I have been experiencing with my G36 new modem replacement modem as well as the old G36 connectivity performance speed issues, issues of every kind rebooting issues you name it everything over the last 6-7 months for which I contacted Arris about this issue there head tech Joshua at phone number  [edit: removed personal information] he told back then he knew NOTHING about these issue with arris G36 modems and the new 10G xfinitys system upgrade which for us has been a very serious down grade with the Arris G36 modem. We are hardwired ethernet connected  and had for over a year with this G36 and on the ISP service at the 1200 Mbps down and 40 Up of xfinitys good performace over all of 1400+ solid flat line at 1400+ continously with same with the 42 up. We need even much faster speeds but this is the fastest available here from anyone. However in July of 2023 is when xfinity up graded there system making there system only compatiable with there modems causing all 3rd party modem incompatible. When these issue occured back in July of 2023 I contacted Arris support which indicated they knew nothing about this which was a lie because they were notified about this by xfinity did with all 3rd party modem mans. So now they have reported this and have been working on firmware up dates to make them compatiable but still have not come up with anything that works yet. Or xfinity is F*#+ing them. I hope at this time that Arris will be replaceing all of there modems that are not working on the xfinitys system with ones that will like the G54 that should be compatible we shall see.