Buying a nas is easy. Most of them support backups. The good ones support containers which takes some of the pain out of what you're working with.
But the nas are fairly expensive, They don't have as long of a lifespan as you would expect. And then you're also beholden to the company for updates, and policy changes. (Synology is currently on their way to requiring you to use their own branded drives, you didn't used to have to do that but they're slowly taking away features)
Only you can decide what makes sense to you. Hey Naz is an easy, slick solution where you're putting the care and ability for long-term access in someone else's hands. Building your own system even with something like unrade is still a hell of a lot of work. But then you get to decide how everything works.
Do what feels right for you.