Connection randomly slows to unusable speeds (10-15 minutes to load google.com)

I'm a pretty new Comcast Business customer (about 2 months now) and twice within that time period I've had my connection basically become un-usable. (Both times were around 9pm pacific time coincidently.)

In both occassions, reseting all the hardware did nothing immediately but then the issue resolves itself 1-2 hours later. As such I canceled the technician appointment figuring the problem is solved. But tonight it happened again and I want to get to the bottom of it and avoid it in the future.

I noticed that I can ping my router fine, and I can ping my comcast modem fine, but if I try to ping anything else I get severe packet loss. (90%+)

When I signed into the modem interface, it seemed that I didn't have a the following assigned, they just showed ---.---.---.--- for both.

WAN DHCP IP Address

WAN DHCP Default Gateway

My understanding is that when the modem connects to the comcast DHCP server for my area, it should assign these to the modem but it doesn't seem like this is happening 100% of the time. Can someone investigate why?