Convert timestamp to a specific timezone in simplified extended ISO format

Hello,

I'm working with an external API service that requires that dates passed into the API meet the following criteria:
1. Dates must be formatted in the following way: {yyyy}-{MM}-{dd}T{HH}:{mm}:{ss}Z. This is the simplified extended ISO format, and an example will be a date like '2019-08-23T04:00:00Z'.
2. If the date being passed into the API isn't in GMT time, it must be converted to GMT before passing it into the API.

I tried using the format_timestamp feature as seen in Snapshot #1 below but it doesn't turn out exactly as the format I'm looking for (see Snapshot #2). It has no 'Z' and it also has a +00:00 appended at the end which is not the same as the format I'm looking for in #1 above.

Any help will be greatly appreciated.

Snapshot #1 (format_timestamp)[image.png]
Snapshot #2 (result)[image.png]