I used a Rasberry Pi 4 to make a pi-hole ad blocker.
I then learned you could just plug in a harddrive to it (USB) to make a very simple NAS. I bought an SSD to USB case/adapter, and with basic tutorials online I now have a network drive. To reiterate, I have no programming skills. Both the pi-hole and now the NAS were from copy-paste command line walkthroughs.
It's not a fancy "NAS" as far as redundancy or backup, but now all 4 of the gaming PCs (wife and kids have their own) can connect to the same drive for sharing stuff. I also use it to manually back up all our photos/videos. I love it.
I don't have a NAS yet, but I've been interested in one as well as PiHole for a bit. I have 2 Raspberry Pi 3b+ currently and have muddled my way through setting up Octopi for a 3D printer on one and setting up ADSB plane tracking on the other. Mostly copy-paste commands as you did on both of them using PuTTY. If I ever get a Pi 4, I'd be interested in doing what you did with yours. Any resource suggestions?
I doubt it's very intensive if you're only doing a single drive NAS - but I did get the Pi4 with 4 GB. It's been running the pi-hole and network drive nonstop for 2 years, no issues.
and of course - enjoy!