Applying the KISS principle, here is what I would do

myprogram.pl alltheoptionsineed.json

myprogram.pl alltheoptionsineed.yml

myprogram.pl alltheoptionsineed.ini

myprogram.pl alltheoptionsineed.xml

myprogram.pl alltheoptionsineed.pl
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In myprogram.pl you get the options by using Config::Any on the filename in @ARGV, along with defaults gotten by File::UserConfig -- least work possible :)