If you are the only user in the workspace, you shouldn’t need to overthink date-time fields. On the UI (and when importing) Fibery will treat them as local time, so just forget about UTC.
Yes, it converts the date-time you provide into a date in UTC which it stores in the backend, but when you’re looking at data on the UI, it converts the data stored in the backend back into local time.
The problem comes with formulas that result in numbers or strings instead of date-time. These will always be based on the backend, since Fibery is designed as a multi-user platform, and it cannot always be guaranteed that all users are in the same timezone.
See this reply.