How can I identify an SMD chip on a buck voltage regulator?

I would like to get the chip part number, to get specifications, for a buck 5V regulator module. I have searched the letters and numbers on the chips (DKAA6 or 1AGCN), but no other reference could be found.

How could I find out what this is?

With markings that do not show up in generic searches the best thing would be tracing it back to the origin manufacturer. Sometimes they would have a record to support a positive ID on the part.

In this case, DKAA6 does not bring to mind any parts that I was able to tie to your voltage regulator. As your photo is showing the module as a complete unit, you may find it easier to substitute a different voltage regulator instead.