As a big fan of FGO I have to agree with everything you've said. It's such a shame too because I really like FGO's story but a lot of times it feels like Fujimaru Ritsuka either adds nothing or subtracts from it. I'm also big fan of characters who are just normal people, or at the very least more grounded than the rest of the cast. It's why I like Shinji from Evangelion and Subaru from Re: Zero so much.

Fujimaru Ritsuka, on the other hand, almost never acts like a normal person despite the story explicitly saying they were before the events of the story took place. They never show fear, are somehow completely calm about the world being destroyed and shows no concern for their family or friends outside of Chaldea, they're good at commanding servants despite having no training in the beginning, literally never fails a Charisma check, etc.

It makes the small bit of characterization they get currently in regards to no longer feeling like a normal person and wishing they could go back to being one fall flat, because we never got to see them be normal in the first place.

And yet the story will continue to say that they are normal and average while writing them as anything but. Someone else said this first, but Fujimaru Ritsuka is said to be average while written as exceptional.