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 well😆
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 ! 💗