How to find specific time range?

we assume that some dynamics are expected and when months do have a different end date like 31,28/29 the statement should also work

we could reformulate also the requirement:
When checkDate (e.g. Today) Day In Month < 7
Then: Today
Else: last Day of current month

So we can formulate this oneliner:
grafik
IF(now.Day < 7, now.AddDays(- now.Day + 1).AddMonths(1).AddDays(-1).Date, now.Date)

Other case test:
grafik

A february test case: