@Mkstretch 

If you unplugged the extender and your wired devices have reduced speed contact Fios, there may be an issue with the modem. The extender only works off of a wireless signal, and will extend the signal. If you have a situation where using the extender lowers your speed compared to be directly connected to the rouer. Then you do not need to utilize the extender.  An extender would be for situation where a corner of the house gets very little to no signal at all.

My speed from Verizon to the router is full speed. But when I plug my windows laptop into the router it’s slow speeds.  If I plug in my MacBook I get full speeds.  It’s very strange. I swapped out the router already   Thanks