RS300 not sending the correct speeds but is pulling the correct from the modem,

I just recently moved to a new house where I'm able to get Spectrum internet. I matched up their provided Modem with the Netgear NightHawk RS300 for the 1gb speeds. When I test my internet speeds on the NightHawk app, it shows my router pulling the 1100down/40up/15ping. Beautiful. When I go to my Cat8 Ethernetted computer, I am only getting 350down instead of the 1000 from my service plan. I understand it's up to 1000, but I'm just confused on why my router is able to get the 1100/40 from my modem but isn't able to send it to my PC via that ethernet cable. I'm not the smartest when it comes to these things, so any help would greatly be appreciated.

PS: I bought a USB ETHERNET adapter thing to see if my ethernet plugin on my PC may have been defected, but I'm getting the exact same speeds, so not that.