Yep, I knew this was Comcast/Xfinity just seeing the title. I had the exact same problem, for years. Intermittent disconnects for a few minutes at a time, multiple times a day. I must have had upwards of 50 technicians come to my house, all insisting there was some problem with the wiring in my house (there wasn’t) or the router or whatever (hardware all replaced multiple times including the wiring). Eventually after years of complaining that the issue isn’t in my house, they finally sent a bucket truck a half a mile up the road and the problem was fixed in about 30 minutes. It worked well for about a year and then started happening again. They started giving me the run around again. I had appointments scheduled for technicians to come, three times in a row they just never showed up. To “apologize” to me they said they would provide a credit on my account. The amount? 1 penny. I took a screenshot and saved it in case anyone thinks I am making this up. Luckily, by this time starlink was available in my area. I switched to that, turns out it’s much cheaper anyway and since then have not had any issues. The sooner Comcast goes out of business, the better.
Tip to anyone reading this: After I cancelled and closed my account, they billed me one last time for double my monthly bill ($200). No idea why, probably they thought they'd try to get away with it. I had little to no interest in participating in their customer support circus again, so I just went online to my bank and submitted a dispute of the charge. The bank instantly ruled in my favor and closed the case, issuing a permanent credit. I have never seen that before. They must be getting tons of Comcast chargebacks to do that.
I also submitted a complaint to the AG office and my local commission but I'm not expecting anything to happen.