Put the nas and router where the internet comes in at and the just use WiFi for your office and the rest of the house. Thats what 99% of the people do. All the new WiFi routers are really efficient at beam forming and other technologies to get you a decent signal.
At my house, since it is raised up I was able to crawl under and run Ethernet to the living room for the htpc(gaming) computer and it was pretty easy to install a keystone next to a power outlet. Not sure if that is viable in your situation.
But even then I didn’t bother running Ethernet to all the rooms because even streaming 4k video is viable over WiFi. Though I understand it might not work so well if trying to edit on a nas or something similar.