Those glass doors are a bit 1990s office block though. Maybe a wooden frame with glass panel/s??

I would clean the lintel and keep it natural stone, paint the frame black and the door F&B vardo.

The thermal qualities of new ones would be preferable. When I had new patio doors (sliding) I couldn’t believe how much cosier the room is now compared to the old 1980s one. Your examples are beautiful. I recently had one of the large double glazed panes changed to accommodate a cat flap (safety glass cannot be cut) and I was quoted £370 - £650 for one pane. I chose the cheaper quote but just to let you know of possible costs to change the glass.

I think the height is irrelevant because every door is different. So I think you have to buy a long spindle and place the knob or handle in the centre of where the cross bar would be (if it were a solid door rather than hollow) This picture of an old door shows the traditional placement