For gift ideas, I think traditional gifts would be a wonderful choice. Such as beautiful Kimono or Yukata, a high quality Japanese tea set, Ikebana Kit or for food items you can consider Wagashi or a bottle of Premium Sake. You can also try cooking traditional meals for her which she likes.
In Japanese culture, the way you present a gift is very important, so it's better if you learn some special wrapping techniques as wellđ
Also giving gifts during special occasions can have more meaningful impression. So consider any special day like Oseibo, her birthday or Mother's Day.
I hope this captures what you are aiming for ! đ