Easy mode: find a triple radio mesh wifi system and get at least two nodes. Generally the LAN Jack on the satellite nodes will bridge to the LAN over WiFi. Just add a switch and use it normally. This will harm your overall speeds when connecting to the NAS from other wired LAN systems that are not on the same switch. I'm not sure if that's important. As long as your internet speed is less than half of your WiFi speed, you shouldn't really notice a difference.
Medium mode: buy MoCA adapters and use coax. Just be sure to get relatively new ones. They're generally all 1G minimum, but usually half duplex, so there's still sacrifice there, but MoCA is generally better than WiFi. The pinch is making sure you stop the MoCA signal from exiting your premise. You don't want to tap into someone else's MoCA network, nor have them tap into yours. There are cable filters that will accomplish this, or you can air gap the coax. I'm not sure how much control you have for the ingress/egress of your coax lines. You can yolo it and just hope for the best, but I can't recommend that.
Hard mode: do ethernet anyways. Usually in rentals, nobody can complain with holes in the walls the size you would get from nails to hand pictures, not much larger than a picture hanging nail, is a cup hook. What I did at my old place, which was a rental, was to buy large cup hooks, and put them every ~18" down the hallway, and load it with ethernet cables. I used adhesive cable runners to go down walls near doors and ran the cables under doors to get from room to room. I got lucky that two adjacent rooms shared a phone jack and I replaced the faceplate with a quad port Keystone faceplate on each side. One Keystone was wired to the phone line to keep existing functionality, the rest were connected to eachother though the wall as ethernet, and I just patched one side to the other (on one side was the core switch for my network). That was my experience, obviously your experience will be different. I used white ethernet to try to blend it in with the ceiling/walls which were off-white. In my situation, I was on DSL and used the phone jack in one of the bedrooms for my internet connection, that bedroom was used as an office and it neighbored my bedroom where I used the jack to jack connections through the wall to feed my TV and other stuff in the bedroom. The ethernet on the cup hooks went from the office to the living room where I put a second access point (first ap was on the office) and TV and other stuff. Inbetween the bedrooms and the living room was the kitchen and the wet wall was basically RF blocking, so I needed an access point on either side, so one in the office near the bedroom and bathroom, and one in the living room, provided plenty of coverage for the ~900sqft apartment we were renting. Most everything was on wired ethernet, and the WiFi was used mainly by laptops and cellphones.
I live by the philosophy of wired when you can, wireless when you have to. Mainly to save WiFi channels and bandwidth for devices that don't have an easy alternative option like mobile phones and portable computers.
I don't think you're in a bad spot OP, and any of these choices should be adequate for your needs, but that will vary depending on what speed internet you have, and how much speed you need for the LAN (to the NAS and between systems).