It seemed that I had a similar issue here:
https://forums.verizon.com/t5/fios-internet/fios-g110-router-ethernet-connection-cycling-on-and-off/td-p/834327
But I need my computer to work on 1000m/s and have no intention of "100 Mbps Half Duplex".
this is 2022 now, you haven't got it fixed fix?
Cycling between different link speeds is indicative of either a bad Ethernet cable or an oxidized Ethernet port. Try to change a cable and/or remove some oxidized metal on the port pins.
