The German Catholic monarch born in exile would most likely be either the lat e Otto von Habsburg or the current Karl von Habsburg. The Wittelsbachs don’t meet the ‘exile’ element as Franz was born in Bavaria. The Hohenzollerns are, of course protestants as are the Saxe-Coburg-Gothas (currently calling themselves Winsors).
Trump has no royal claims.
Since I am a bridge player...TRUMP has special meaning for me. He is the King of Trump. Long live plays the king of Trump.