large storage server recommendations

[Korneel]

hi brain trust;

i already went through a lot of the forum but can't seem to find an answer.. hope for some good recommendations;

I currently run a Synology DS3615XS with 1 expansion bay, 2X 12 disks in RAID 6, so 2 different arrays, around 200 TB in total. 

i need to move away from the Synology and with all the consumer unfriendly stuff that has been going on, i want to move to a different system. I have already invested into hexos and bought a perpetual license. while it would be nice to have the NAS run additional software in the future, for now being a SMB is enough for me. I run all my dockers on a different MS-01 from Minisforum that has all the processing power i need. 

so, what am i looking for?

i am looking for a storage server. ideally rack mountable with half-depth, quiet and simple. if possible 24 disks so i can expand.. i would need at least 200tb as a starting storage pool and be able to expand later on. I was hoping ubiqity would release an enterprise version of their NAS since it does everything I need, is cheap and super simple but alas.. 

while i can figure out most of it, it's the chassis that has me scratching my head.. 

does anyone have any recommendations?