The modem is actually compatible for Gigabit, I just don't pay for the service, just the 300/30 service.. My desktop is the only device actually wired into the modem via CAT6, but assuming faulty hardware (KISS troubleshooting) I verified both my LAN device and modem are operating without issue and all the ports on the modem are working. With that being said, I did do tests with my laptop over the WiFi and the results were similar, although the speeds were different, which is to be expected when comparing WiFi to CAT6 speeds. Prior to COVID, my speeds were consistently close to 300 down nearly all the time (maybe 200-ish during peak times) and there has been zero hardware or configuration changes. It's only within the past two months that issues have started. Again, I realize with everyone home, the nodes are going to be experiencing more bandwidth usage, so speed may not be completely optimal. To be honest, this would all be fine if Cox was more honest about it. Especially if there was a disclaimer that temporarily high bandwidth services will have reduced functionality during this time. Thank God I pay for VPN...
EDIT: I see you're a Cox employee, so that's why you can see my modem, I assume. The DOCSIS 3.0 AC1900, is more than capable of a 300 down plan. If anything my modem is overkill for what I actually use it for. In checking the configuration, it appears it's configured currently for up to 1,300 Mbps at this moment. My LAN device is also configured to up to gigabit speeds as well.
EDIT #2: One thing I forget to mention, with my baseline test, the two cellphones in the house were removed from the WiFi and the computers connected to the internet were passively using around 20 to 40 Kbps (which we're talking a fraction of a fraction of 1 Mbps), but not actively downloading, browsing, or streaming media. So, for all intents and purposes, my baseline was based on almost the absolute minimal internet traffic and during my test, it was my desktop (figured it would be the best for getting the most consistent speeds being the only wired device), that was the only device actively using the services I described above.
