This is nothing more than a file server so nothing much to worry about.
Your network latency can indeed play an important role. You can reduce this as much as possible by keeping the NAS and the NUC on the same switch. Moving them to different switches will add latency. In addition if you woud connect 2 say 8-port switches all devices on 1 switch will need to share the 1Gb connection to device on the second switch. In theory that should still be sufficient, but if you can avoid it I would.
Having a separate SSD with storage on NUC is also a great option. If you choose to go down that route, you can still use the backup purposes.
Be sure to check out the RHEOS extension. You can run it in a Docker container on your NAS.