I used to work for a cable company. Most all of the time amps were not necessary and deployed in the wrong place. You really need to know if you need one in the first place. Let the cable company determine that, do not buy one on Amazon and hook it up yourself (in my day it was radio shack amplifiers). I can't tell you how many I used to pull out of houses and throw in the trash. Problem with amps are that they can introduce noise and overdrive your signal. Also I used to find them behind modems or TV sets. You can't amplify garbage, you will get louder garbage. Also they do not amplify the reverse path and that can cause issues.
In your case it is definitely not needed based on your before and after screenshots. It's likely everything else cable wise on your home will be a bit more stable now...
Slightly off topic but here is my PSA for the day regarding cable troubleshooting if you want to read further.
Example: on the downstream you have - 2dbmv at the ground block (where the cable enters your house) subtract another 3dbmv for cable attenuation. You want every outlet to be "live" in your house and you have 8. Subtract another 10.5dbmv. So that means you are down - 15.5dbmv from the entry point. Add a +15dbmv amp and you are at - 0.5dbmv for each outlet, perfect right?.
The issue is the upstream, let's say your modem is transmitting at 45dbmv if you connect it to the ground block with no splitters. It has to transmit at +60.5dbmv now to overcome the 15.5db of attenuation from the splitters as amps only pass reverse they don't amplify it. Now your modem cuts in and out becuase it has reached its max transmit capability.
