WD80EZAZ and the other WD 8TB white label drives that come from MyBook / EasyStore are essentially WD Reds. Some of them are true 1:1 relabels, others are slightly modified from their WD Red counterparts, like the WD80EZAZ.
WD80EZAZ (white, 256MB Cache, 5400rpm) features PWDIS feature (Power Disable aka "3.3V") and comes with TLER disabled by default, while its WD Red counterpart WD80EFAX (quietly updated Red, 256MB Cache, 5400rpm) doesn't have PWDIS and comes with TLER enabled.
PWDIS feature requires PCB and firmware changes. Additionally, WD80EZAZ has a slightly different firmware configuration, like TLER beeing disabled by default. Thus, it's safe to say they're not identical, as you might not be able to recover a dead WD80EZAZ by using a WD80EFAX PCB donor, but they're still very close to each other.
WD Red 8TB are HGST He8 / He10 OEM products. WD80EFZX is He8, WD80EFAX is He10. Publicly available documents might only list 7200rpm for OEMs, but as WD owns HGST, they obviously have more options available than your average OEM. As a result, it is true WD80EZAZ (white) are HGST He10 OEM harddrives. However, WD80EZAZ is not a relabled WD Gold 8TB, as those are running at 7200rpm.
the fact that the tler setting doesnt hold over power downs is indicative of it not working at all, just being able to be set temporarily visually.
Can you give us any evidence? What's the point of HGST / WD creating a product, which reports TLER support, lets you enable it, but doesn't function? From what I've seen so far, it looks like WD80EFAX and WD80EZAZ are actually using the same firmware, only differing in their configuration (NVRAM). So, having TLER enabled, they should both act the same.
Until there is
clear evidence, that white label WD 8TB drives indeed have a modified firmware module, where e.g. TLER function has been zero'ed out, this is just a conspiracy theory for me. To prove that, one would need to dump WD80EFAX and WD80EZAZ firmware modules and compare them. Clearly a job for an expert with access to low level tools, like PC-3000.