Slow upload speeds (again)

Hi, a couple years ago I was experiencing slow upload speeds. I made this post and eventually everything ended up okay: https://forums.cox.com/forum_home/internet_forum/f/internet-forum/18313/very-slow-upload-speeds-download-speeds-are-fine

By okay, I mean that I was mostly getting a 10 Mbps upload (which is exactly what my plan supports). That lasted up until recently, and I'm experiencing similar problems again. My download speeds are fine, but my upload speeds never seem to hit 10 Mbps anymore and instead hang around 2 to 7 Mbps. The lack of consistency is quite troubling to me and that's why I think this is an issue.

I looked at my modem and saw that over the past month and a half, there's a lot of critical errors, such as T3 timeouts. If you guys want me to produce a log, I can. It has also been incredibly cold here recently, which I know can have an effect on internet speeds, but I feel like it wouldn't matter here since my download speeds are perfectly fine.

Here is a screenshot of my upstream/downstream channels. This is after a reboot initiated from the Cox website about 30 minutes ago: https://imgur.com/a/yjmLq9Z

Can I get some assistance on this? From your point of view, I'd like to know if anything looks wrong. My modem and router have stayed the same over this period of time.

Thanks!