There are no Germans any more in Deutschland probably since King Charles the great, more than thousand years ago.
Calling Deutschland Germany and Deutschlander Germans would be like calling us England Anglo Saxony. There are no anglo saxons any more in England probably since William the conqueror thousand years ago too.
So the best inter state abbreviation of Deutschland would not be D, de or ge or ger, but DL!
All Deutschlanders are free to rename their state and country Germania of course, if they dare!