Did I read somewhere there are two work/office locations?
You could simply get a LSI 9200-4e4i - the 4e is the 8088, that'll go to your DAS. The 4i is the 8087, you could connect that to a SAS expander internally to get more HDDs connected internally. I've bought from jiawen2018 on eBay..like..at least 5 times, all good quality gear.. eBay item # 142620883440 would be suitable (under USD$30). Just need a 8087-8087 cable to connect HBA to expander.
you're going to run truenas? so ZFS is gonna be your file system?
If so, here's what I do (I use ZFS)... plug 'em in, run a SMART check (just in case DOA), then BAM straight into production.
No bullshitting.
I have had HDDs pass badblocks, & still fail ZFS. Seeing as it doesn't get much more strenuous than badblocks, why tf should I bother if even bb isn't weeding out the weak drives? I have back-ups, so I have nothing to worry about. Just straight in, ZFS will sort 'em out.
If you're using ZFS, dont' bother with all the fluffing about of testing etc. ZFS *IS* the test.