I am one of the first subscibers and have had fios for many years now.
We had periods of loss of internet constantly, wired or non, didn't matter. My setup had the Verizon router connected to the ONT via coax. The location of the router made it useless for wireless in my 3 story house since it's in the basement, so I also have an Eero wireless mesh in "bridge" mode installed throughout the house. I had already turned in my fios tv boxes in favor of my own streaming content and when we watched things at night there was constant spooling and outages. Yesterday I devoted the afternoon to get to the bottom of it.
I did a speed test on a couple well known sites and although I pay for 80/80, my downloads were only 10. Half of the speed tests failed. I got on the phone with a fios rep and she had me test and all the speed tests against the verizon site was failing but she and her network tech assured me that everything looked good from their end. I've been wanting to eliminate the useless (to me) verizon router for a while so while I had her on the phone I asked her to change my ONT from coax to ethernet. She did that and guess what. I wired directly into my Eero and for the first we have the excellent 80/80 speeds with uninterupted internet 24/7 that I knew FIOS was capable of. My father has the same problem and the same type of Actiontech router and I'm going to fix this for him as well. I hope this helps others out there.