I’d definitely recommend to first remove all addons fully for a test (disabling won’t do) since every addon does have the potential to trigger such a result, and see if that makes any differences.
if it does not, the next step would be to reset all CVARs to their defaults, via the following commands:
There may be some warnings popping up about missing permissions on the reset, but those can be ignored - the CVARs relevant to the topic will still revert to their defaults.
That is correct. There were never any boss frames in original Wotlk and they do not exist on Wotlk Classic either, as intended. Boss frames came with Cataclysm.
Sorry support is giving you bad advice to delete your entire UI.
This is the new Blizzard CM experience unfortunately. All AI bots.
Same thing happens if you submit a ticket. You get this odd response that appears as if the “person” never read your ticket at all.