Netgear C6300 firmware update

I own a Netgear C6300BD, it works fine, at least for downloading speed.

However while videoconferencing people tell me they hear me stutter (my voice drops every few seconds), regardless of videconf app (zoom, teams, whatsapp, etc.), or device.

The current firmware is 2.01.08.

On the manufacturer's page says the latest firmware version for Comcast is 3.01.12

https://kb.netgear.com/000036375/What-s-the-latest-firmware-version-of-my-NETGEAR-cable-modem-or-modem-router

However I haven't been able to update it.

I've tried.

1. Rebooting it.
2. Reseting factory settings.
3. Using the xfinity devices management page. It says "There's a problem with your modem", but after clicking "Let's fix it",  it tells me to call customer support.
4. Calling Comcast customer support (they say call Netgear).
5. Calling Netgear customer support (they say call Comcast).

Just to be clear, I can connect fine, and I have good downstream speed, the main issue seems to be upstream stability, which is frustrating while videocalling.

I want to know:

• Is it C6300BD different than C6300? Is that why it's not updating? or not recognizing the modem?
• Is there any other way to get the firmware update?

PS:

On the xfinity devices page, the modem shows up as "Cable Modem NETGEAR NOMODEL", so I guess that's the main issue, Comcast can't push the update because they can't know the modem's series?