Please try:

=ARRAYFORMULA(ISDATE_STRICT(A1:A11))

The function is currently not documented.

: ISDATE_STRICT wont let date&time format, dates only

1. Do not know the reason, still curious.

2. Workaround: =FILTER(data,IFERROR(DATEVALUE(data))) was found here

Note: Workaround will NOT work for dates formatted as:

dd.mm.yyyy

You may use a duck-typed workaround:

=FILTER(data,REGEXMATCH(MID(data,7,4),"20\d{2}"))

Will check if formatted date has a 20XX year string inside.

A workaround that could work depending on what you're trying to do as far as Arrayformula is concerned

=ARRAYFORUMLA(ISNUMBER(VALUE(data)))

• VALUE can turn the time into a number
• ISNUMBER checks if it's a number
• ISNUMBER works fine within ARRAYFORMULA

Now you can convert any formula to arrayformula:

=BYROW(A2:A12,LAMBDA(r,ISDATE(r)))