Intermittent extreme slow speed Issues while connected to a VPN.

TLDR - I work from home and my company uses Cisco AnyConnect VPN. I frequently have intermitted connection issues while on the VPN, especially during video conferences (and off it). All other devices in my home will be fine, and show fast speeds. I only have issues when using wifi. Speeds are fine when I'm hardwired to the ethernet. I have tried contacting customer service to talk to someone with some technical prowess to no avail. 

• This has been occurring since I got Xfinity 2 years ago. I have no other choice in ISP where I live. I had zero issues doing the same activities with the same computer (albeit a different VPN) at a previous address where I did not have Xfinity. 
• Now, every couple weeks, I will have issues on the laptop where I use Cisco AnyConnect VPN with my wifi connection. I will have ungodly slow speeds only on that device. The other day I clocked something like 5 mbps download and 0.5 mbps upload. All other devices in my home will have no issues and much faster speeds (250 mbps download/16 mbps upload).
• So far, I have noticed no issues when I hardwire this laptop. 
• I checked my modem and router as well. Modem is brand new. Again, no other devices in my home have any issues unless there is an outage. I ran the Xfinity assistant tests as well and every time I ran those, no issues came up.
• I reached out to my company's IT department to see if this is a VPN issue. They have let me know that it is not, since my connection is completely fine when I use the same device in the office with both a wifi and hardwired connection. I have completed all other possible troubleshooting steps such as restarting modems, routers, the laptop itself, etc. I have installed every possible driver and update. The issue ONLY occurs when I am using my home Xfinity wifi connection. 
  • The network ops team at my company suspects the issue could be due to the VPN making the network traffic look suspicious, causing it to get flagged by the ISP, which is sometimes resulting in the slow, throttled connection on just that device.

Happy to provide any further detail but I am completely at a lost and would really appreciate some help as this makes it extremely frustrating and difficult to do my job.