Those arches look structural, so cutting into them would be a major project requiring a skilled contractor. And afterwards, you could have settling in the brick work that remains, which could produce noticeable cracks. If it were me, I'd leave it alone. I understand your desire to have a modern look, but this is a project that may not only be expensive, but one you could come to regret. Sorry, but that's my two cents.

I would set one big window instead of arches , and expand the interior space

O need to know if they are the only arches on the exterior . Yes thye are structural but that can be changed to less obtrusive handling of that area,Could you post some pics in a comment here of the whole house and on a sunny day so we can see the whole thing.Is there an actual space behind those arches like a balcony?

I don't think the arches can be changed much either. Looks like your balcony might be around 4 feet deep, maybe 5? It's kind of hard to tell, but your balcony furniture looks substantial enough for that depth. Are the shadows on the end walls indicating openings in the walls, or shadows of other?

What do you want from that space? Do you often use the space? Prefer to leave it open, or open to closing it up with windows? Is that solid railing for privacy, or are you OK with it being more exposed? If it's for privacy, there can be more modern options. If not, it should still go. If they are in good shape, consider painting your window and door frames and trim to match. A lot of more modern treatment has all of it being one color instead of light framed in dark. If they aren't in good shape, now might be the time to consider replacement.

While you are thinking about the tops of the arches, also consider the bottoms of them. The garage doors. Those could use a fresh painting at least. Also, if you change the railing up top, consider the railing down the stairs. Right now the two different styles are not helping bringing it together as a whole look. Your lighting is also rather traditional, and could be swapped out for something more modern.

The best idea I've seen for arches like that is to remove the railings and fill the arches with plate glass; making it into a sunroom.

Some visual

The above rendering let me know, immediately no to that concept, it looks forced and does not update that house in anyway. There would be so many other things to spend money on here that would give this house much more appeal, not remove the character.