My plan has much lower upload speed that it should

I've attempted to use the chat feature but it is broken.

After speaking with someone else in my area who has the same internet plan as I do, I realized there is something wrong with my internet plan. This is not a technical issue but the plan itself. I also found other information that indicates the gigabit plan should at least have 100 Mbps upload, however my plan only states that I have 35 Mbps and in actuality I can achieve roughly 50 Mbps. Download speeds are roughly the what the plan states at 1050 Mbps. I cannot find any information anywhere in my account about why my plan has unreasonably low upload speeds.

What can be done about this?

Edit to add this is, to my knowledge, NOT a local equipment problem. I have a Xfinity approved (from their own official list) Motorola MB8611 DOCSIS 3.1 modem. Docsis 3.1 has a theoretical upload speed up to 1.0 Gbps so the modem is not the problem. My internet gateway is a Ubiquiti Dream Machine SE (UDM-SE) capable of MUCH MUCH faster speeds. The cable modem is connected at 2.5 Gbe. The limitation here is the Internet plan itself and it seems wrongly limited.