Make sure the design accounts for spacing/access in case the window needs to be repaired or replaced. You don't want to have to remove the backsplash to do that.

I wouldn't want quartz as a backsplash behind a gas range, because there is a potential for scorching. I would just tile the area under the cabinets and under-hood tile. Window treatments are a personal preference, but I wouldn't use any if I didn't need privacy or sun control and even then I would prefer to have a shade.

If you didn't want tile, you could do something like what P. Allen Smith did in his kitchen for backspash and window treatments. https://simplejoyfulfood.com/tiptoeing-through-p-allen-smiths-kitchen/

Concur with theresa21- I would not do quartz behind a range because of the potential scorching. Would also not do quartz trim around windows, but would do wood trim in a style compatible with that of your home.

@Sandy Mendoza. Did you do the wood or quartz trims around windows? Would appreciate if you could post some pictures.