You have a lot of unlocked channels and errors in the line.
Not a ton of errors but coupled with the unlocked channels, it can be a line issue.
Start with removing any amplifiers, signal attenuators, or splitters from the coax.
From there check the line for kinks, damage, moisture in the line.
Check the connectors for improperly made ends, foil touching the copper coax line, bad/old/cheap connectors, or corroded connections. Replace them if you do.
If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.
And if your ISP straight up says "its not the line, its your modem", then try renting a modem from them for a month. If everything works as it should for the whole month, it sure could be the modem. Its not unheard of. And if it has issues, then they can't blame it on the modem.
