New build - Direct play

In light of the recent GDrive changes that are coming, I’ve decided to move all of my content local. I had over a PB of content available via the cloud and I’m not expecting anywhere near that type of storage. I have a lead on two QNAP devices (TS-853BU-RP with 48 TB and TS-859U-RP with 12TB), the smaller one of which would be free. I’d like to house around 40-50TB of content of possible, mostly x265 content varying between 1080 and 4K atmos. I’m running multiple shield devices at the house (1 2017 model and 2 2019 Shield TV models) along with the latest Roku Ultra in all other rooms. I’m just looking for something to serve up media locally, nothing being shared external. I’ve had it pretty good with Sonarr, Radar, Omni, etc. so I’d look to replicate that as much as I can. Is it worth snagging those 2 QNAP devices, or am I better off starting from scratch? I have around a 1k budget. Thanks!