Have the UTC or GMT values been added as accepted GENERIC_TIMEZONE options (as mentioned in Default Timezone Issues)
When I set either of these as a variable, I still don’t see this option in the Workflow pulldown and the pulldown reports Default - Default Timezone not valid
As of version 1.81.0 (which is the version I am currently on), no, you still cannot use UTC, and the error you are seeing is the same I see, when attempted the same way you are attempting.
I don’t think there can be a “no TZ” option. Every workflow inherently needs a TZ. It just defaults to Eastern US, for some reason I do not understand myself (popularity? appeal?).
The Etc/UTC option is now visible/valid within the workflow, but my execution logs still display in local time. New n8n user here. Am I missing another setting?