I'm a proponent of a do it yourself NAS using FreeNAS or Unraid. I had a standalone NAS and got burned by a ransomware attack due to a vulnerability in the software for a feature I had "disabled". There was zero way for me to know it was an issue without checking the vendor's forums and seeing everyone else who had the same issue. Upon looking into it a bit more, it seemed like most standalone commercial NAS companies had been hit at least once.
Doing it myself means that I know how it is setup and can control what has access to the internet. As a benefit, the old computer I used performs way better than the standalone NAS and is way more stable (my old NAS "lost" docker containers multiple times). I can definitely recommend Unraid as being easy to use which has a ton of resources on their website and forums, as well as many videos on Youtube on recommended setups. It was definitely a good learning experience and overall not too difficult to do.