While importing data into a DateTime field in Archer the value you specify inside the import file will be considered as GMT and will be pushed into DB. This article provides a workaround to import the date & time specifying the timezone.
There are a couple of options for importing the date with the correct time zone.
Import the data from a data feed or an import with the time zone included. For example: 4/5/2019 7:00 AM EDT
Apply a calculation to your date field in a Data Feed. Here is what the calculation would look like:
CONCATENATE([Date Field]," ","EDT")
The time will be imported as whatever time zone you specify. You cannot use ET so you would need to use EDT or EST depending on the time of year. Attached is a sample application package and dfx5 to explain this.