Not Getting Advertised Upload Speeds

Hello!

I had an 8 year old modem and router setup, and I was paying for the 800 down, 20 up plan. With my old modem, I was not getting the download speed that I was paying for (usually around 250ish down and 22ish up). Yesterday, I purchased a new modem (Arris Enterprises S33 DOCSIS 3.1 Cable Modem) and router (ASUS RT-AX5400), and after getting everything setup, I was getting around 900 down and 22ish up. Great!

I then saw that I could upgrade my speed to the 1 gig down and 150 up for effectively 20 bucks less per month, so naturally I hopped on that bandwagon. I received a confirmation email where it states the whole "up to 1 gig down and up to 150 up". Now, I understand "up to", but I'm still only getting the 20 up that I was originally getting with (a) my old equipment and (b) my old plan. I wasn't expecting to get the 150 up, but if I got around half of that I would have been happy. I tried resetting my router and modem after upgrading my speed, but that didn't help.

There is an Xfinity store by my house, so I swung on over there today to talk with them to see if they had any ideas. They showed me that my account still showed my old modem and they said that's likely why; I guess the system was just sending the old amount signal, so they deleted my old modem off of my account so that only my new one remained. They told me to restart my modem and router when I got home and see if that worked.

It did not.

I just have no idea what else could be going on. Any help here would be greatly appreciated! Attached below are my email confirmation as well as my most recent speed test.