Thank you both for the replies once more, and, I must say, for your contributions to other topics too.
I noticed this comment by Michał Muskała, which also seems helpful for my question - Deprecation warning says to use :naive_datetime but I'd like to use :utc_datetime
Just to clarify. The warning says to use :naive_datetime since that’s the type
with exactly the same behaviour as the old Ecto.DateTime.
The :utc_datetime has slightly different semantics.