As I mentioned in my post above, if you use your own modem, they'll blame it. Everytime. Use their modem until you get this resolved.
Cable equipment tends to have automatic gain control, it automatically adjusts the amplification based on temperature or based on the input level on downstream amps, sometimes they may do additional manual adjustments, but there's no conspiracy where they're turning down levels until people complain, people now may be seeing lower more consistent levels than in the past because they've been cutting down how deep they run amps or even going all the way down to Node+0 in some locations. Cable systems have to be very tight and if the signal can get out to interfere strong locally generated signals like LTE and 5G could get in and wreak havoc, also they're really maxing out the low split return anymore and they try to keep stuff super tight because the return path 5-42mhz is really kind of a bunch of garbage full of interference from ham radio and stuff and it's harder to keep out.
Blame game isn't always necessary. A field tech can hook their scanner-whatever up and measure signal strength at the site junction box to determine if the issue is before or after that point in the network... though the problem has to occur while they're there, otherwise it's just redoing as many connections as they can that they are responsible for, which means considering if the customer is liable for any site work within the premises, past that exterior junction box.
I guess the tech was just trying to placate me then. He Installed an older style modem and the local amp and never had an issue after that.
I remember it is about -14dB, at work right now so I can't check real time, but it is around that number. Will check with another 12V power supply and see what's going on. Maybe wind blew out a cover somewhere and water get in.
