If I remember correctly, in one of the vlogs you mentioned something about OpenMediaVault and raspberry pi that maybe one day you will look at it.
If you actually decide to do it, can I suggest you to use Odroid HC2 instead of raspberry pi? In combination with OMV, this is really a good little NAS for soho or as a second backup in a remote location as an alternative to cloud.
RPI especially 2 and 3 are a very weak solution for the NAS as you know. And FreeNAS is unlikely to appear for ARM.
Of course, OMV is not FreeNAS and Odroid HC2 is not a mighty x86 but it also has its place imho. OpenMediaVault for ARM is based on Armbian, in other words, Debian stable. And you as a Debian person will feel like a fish in the water.
Personally, I use OMV + Odroid HC1 and HC2 in several places. Both privately at home and at some very small customers who simply did not have the budget for a large NAS.
Odroid HC1 + ssd can even be stubbornly treated as a mobile NAS. For example, install in your tesla as a mobile backup.