Netgear CM2050V: Faster uploads? Other VoIP Options?

I have the 2100/300 plan and I also have a VoIP telephone line that I need to use as well. I take it the Netgear CM2050V is still the only enhanced speed modem (short of renting Comcast gateway for the rest of my life) that also has a VoIP Analog Telephone Adapter (ATA)? I asked because the upload speeds seem to be limited after a few days of use (I assume a firmware downgrade). As can be seen below, the Netgear CM2050V definitely can achieve the 2100/300 speeds (actually even greater at 2280/360Mbs), but then after a few days/weeks something happens (firmware downgrade?) and it again is limited it to 2100/41mbs. This makes me very sad and unhappy.

I can achieve the 2100/300 again by temporarily installing a Hitron Technologioes CODA56 modem by using Xfinity app to "Add Device" and then I let that get all setup and validate the 2100/300 really does work (actually getting 2150-2200Mbps down and 350-360Mbps up), and then swap back to the 2050V and I'm still getting the 2100/300 (actually 2280/360) AND I have my analog telephone plugged in to the VoIP ATA like I need, and the telephone (used for out-of-band monitoring) works fine too! BUT... then after a few days, everything goes back to slow uploads again and I have to repeat that process to get the speeds back. Boo. :(

Will there be a new firmware for the CM2050V that allows for the faster speeds in the markets it works in (like mine)? If not, is there or will there ever be another non-rent-for-the-rest-of-my-life high-speed upload + VoIP gateway option? Is there a way to have a second device just providing the VoIP ATA gateway while I use the CODA56 for my Internet for faster uploads?

Thank you,

Jay