If it was my first NAS or I wanted max data security I would buy a Synology or QNAP, I have two Synology units.
If I wanted cheap and less secure I would use an old PC and install FreeNAS or Xpenology (Xpenology is very cool but not very polished}. My Xpenology junk build is for non critical stuff like mp3's and security cameras.
My next NAS will be a self build probably with a cheap Ryzen and ECC RAM running FreeNAS or X pen, haven't decided.