I've been using a QNAP TBS-464 [1] for 4 years now with excellent results. I have 4x 4TB NVMe drives and get about 11TB usable after RAID. It gets slightly warm but I have it in my media cabinet with a UPS, Mikrotik router, PoE switches, and ton of other devices. Zero complaints about this setup.
The entire cabinet uses under 1kwh/day, costing me under $40/year here, compared to my previous Synology and home-made NAS which used 300-500w, costing $300+/year. Sure I paid about $1500 in total when I bought the QNAP and the NVMe drives but just the electricity savings made the expense worth it, let alone the performance, features etc.
Thanks, I’ll give it a look. I’m running a Synology right now. It only has 2 drives, so just swapping those out for SSDs would cost as much as a whole 4xNVMe setup, as I have 8TB HDDs in there now.