Modem replacement - Inquiry about XB10 in my area.

I have a complex network with an XB8 modem feeding into a 10G router with wifi 7. I need to send that router in for RMA repair and have discovered that regardless of distance, I cannot get wireless speed to go above 350M (6 foot distance, direct line of sight with the XB8 sitting alone in the middle of the room with no electronic devices within 10 feet). In addition, the wireless signal has latency and when connected to virtual environments I am getting freezing and momentary disconnects. The XB8 has been completely disconnected from everything. allowed to sit, and restarted and even been reset to factory settings, but the issue still occurs. LAN speeds are as expected, and I can consistenly get 2G+ speed from my router, but not the modem. 

This is my 4th modem in the last 15 months (2 XB7s and 2 XB8s). I want to verify that the XB10 is available for my neighborhood in Jacksonville, FL and have one shipped as soon as possible if it is. Otherwise I'm going to have to switch to AT&T fiber as I need a consistent internet platform as I work from home in IT and I don't want to waste 6 hours on the phone talking to technicians who insist on rebooting my modem, even after the IVR has already done so before I could even speak to a live human, and don't know anything about the product offerings. 

Please advise.