your cables inside your house are your property, you may ask comcast to maintain them but they WILL charge you for this. You don't expect jiffy lube to change you wind shield washer fluid for free right? If you go this route clear a path to all active outlets, and splitters inside and OUTSIDE the house. If you stack your boat up over your utility entry point MOVE IT before the tech gets there. If you grow roses there TRIM THEM. Unless yo do nto whant him to have access to do potentially needed repairs.
So there is a lot of missing data, if you have time to post the levels from
192.168.100.1 [assuming your modem shows them to you] that may help also error logs if available. Suspect to see t3 errors but we shall see..
the most common issue is bad or loose fittings. They may be on the jumpers that go from the wall to the devices in your house [note jumpers to tv's or cable boxes being loose can interfere with your modems its called noise, bad fittings on any active outlet can also cause this]. So tighten fittings there are two user recommended ways.
1 wiggle cable with off hand and tighten fitting with main hand this helps unbind the threads and get it on all the way, or use a 7/16" wrench or pliers with MINIMAL force, just the weight of your arm if it moves its loose, use muscles and you change breaking what your tightening it to. The latter way is easier to get right both will work.
The next thing is the heat, its getting warmer could your modem or computer be overheating? try a fan or 2 and see if it gets better or worse.
It could also be the comcast system or drop issues, squirrels chew them, neighbors loose fittings generates so much noise it make sit to the main system instead of just his house and knocks everyone else out. But this is not frequent, its usually a loose/bad fitting on the subscribers cable system at his house that is the issue. Even if comcast installed the outlets YOU own them and are RESPONSIBLE for them. Unless by installed you mean within 30 days.