Problem:
SQL Timestamp field cannot be added to table extensions.
So, this basically means that https://docs.microsoft.com/en-us/dynamics-nav/how-to--use-a-timestamp-field is unusable in a real life scenario at the moment.. Because we would need the field into all tables, not just in the custom ones.

Idea:
It should be possible to expose the timestamp field on all tables as a System field (like for example SystemModifiedAt), so we can use it in pages and data import processes.

Please see this issue for more details where the resolution was that: Microsoft will focus on the "right" solution, exposing the timestamp field on all tables.
https://github.com/microsoft/ALAppExtensions/issues/13474

But we don't have a timeline for this..