@rvdhorst
Your example of days does not match your request...
There are 13 days between Jan 1 and Jan 14. Yet, there are 14 days between Jan 14 and Jan 28!
So the "jump" of days is not the same.
An example formula that would provide a consistent jump of 14 days with a start and end range would be the following:
With({_start: Date(2021,1,1), _end:Date(2021,5,31), _jumpDays:14},
Ungroup(
ForAll(Sequence(DateDiff(_start, _end, Days), 1, _jumpDays),
Table({Date: DateAdd(_start, Value-1, Days)}, {Date: DateAdd(_start, Value, Days)})
),
"Value"
)
)
This will produce a table with a single column called Date. The Dates would be as you wanted based on your description - but not your example dates because of the discrepancy.

I hope this is helpful for you.