^Gudako and Gudao aren't super different in FGO, though how some characters treat the protag has differences, they do make certain unique CGs and Arts for each protag, including ones that just show their command spells (you can tell the protag command spells apart easily), along with certain scenes in the game playing out differently depending on who you're playing, which is something I wish would happen more often but they are there here and there. One of the primary fun elements of the protag differences is the Shinjuku chapter where Gudako dresses in a suit, and Gudao wears a dress. Some of these elements and characteristics are better defined in the manga adaptions as well, as some feature Gudako as the protag, and others feature Gudao. So while the protags for Extra/Extella might get a bit more, I wouldn't say Gudako is just tacked on either as there is some really fun differences.
Anyways, regardless of your opinion on FGO I think we can both at the very least agree that Fate needs more main line anime featuring their lady protagonists.