Is this how verizon install new service by making a split connection?

[ANW1619]

I have 1G Fios and used to have a steady wifi connection speed of 325-350MB on my gaming pc. But Not until one night that I've noticed something fishy. I was in a game competing in S.Asia region with 190ms ping and knew that it will be still playable and I had no issues before. A few minutes into the match got booted with the message HIGH PING (over 300ms). So I went to speed testing sites and find my speed has been dropped to 125MB to 245MB with unstable connections speed and lag spikes. I'm the only PC that is connected to the router at that time so you can rule out that somebody in my household using the bandwidth. I reset the router and the ONT couple of times and had no improvement whatsoever. but the next morning speed went back to 325MB (normal) and the connection was steady. Ok, so I thought maybe there was an outrage that night. So same day that night after my neighbor came home I did another Test and my internet was back to abnormal again. I mean could the peak hour might of causing this? The next day morning it was freezing out and I look outside the window and at the pole, I noticed there splice going to my neighbor's house. Not sure how long it has been there but the speed is back to normal again. The only explanation I can think of is the peak hour and wifi channels affecting the speed but again down by 100MB? Is that how it looks when Verizon tech installs lines for your next neighbor by making a splice?