You're having some pretty bad issues on the upstream, especially with attenuation which should be half of what it is now with a higher noise margin, speed, and lower power. Bet you your Voice service if you have Frontier POTS also isn't the best sounding thing either.
What you can do is take your modem to the NID to see if anything improves out there. If not, you'll be wanting to get a tech out to find what's wrong with your copper circuit.
I am unable to test out in the NID the tech that hooked up our Internet just threw a bunch of wires in there and the Splitter got water in it but after I reset my router my margin dropped and my upload increased.
They should not have a problem replacing the NID if it is old. When we moved in they installed a NID from the stoneage that came with its own prehistoric critters. My circuit was always dropping out, finally convinced them that the NID was the cause of my problems. Cleared up a lot of the drop outs and noise on the line when they replaced it.