As someone else who also plays FGO, I do get some of what your saying, for the most part. I feel like I should bring up 3 major points. The first being Gatcha game is 50% of the reason why we have so many genderbends, the other 50% is because of how the Franchise began. It is what Fate is known for. At times I am surprised we don't have even more Genderbends.

As for the second point, of how FGO has being adding stuff like robots and aliens in, I see it more so as them not really wanting to restrict themselves too much with 'just magic'. It does basically allow them to do whatever they might want, which does help inflate the overall variety up in terms of character gimmicks. Which is a good thing to have in a Gatcha game.

Third being Hades and FGO are two very different products, although both have of Historical and Mythological fiction in their stories, Hades does a deeper dive of 1 Mythology and a few select locations and characters. While Fate goes all over the place, and figure out ways to connect a bunch of different Mythologies and historical characters. I am 99% sure there are games about Japan and Japanese Mythology which are much more accurate than FGO.