Google Sheets Arrayformula for timestamps of checkboxes changed

Question

I am looking for LAMBDA-based formula for hundreds of rows which will add timestamp based on checkbox changed for that particular row.

Need it to be ARRAYFORMULA/BYROW, as number of rows grows dynamically based on underlying data.

Using the following (based on this answer) results in entire column of timestamps changed when only one checkbox gets (un)ticked. While I need each timestamp to be changed individually, according to its own checkbox.

=BYROW(
  A1:A,
  LAMBDA(
    rw,
    IF(
      rw = "",
      "",

      LAMBDA(x, x)(
        IFERROR(rw/0)+NOW()
      )
    )
  )
)