First of all, I really wish you all the best. It is not easy to have such a good relationship in a long-distance relationship. If you can't be together often, it is really necessary to give your girlfriend a thoughtful and meaningful gift. Here I recommend several gifts, I hope they will be suitable for you:
DIY chocolate and cartoon bouquet. You may think chocolate and flowers are too tacky, but what I recommend here is DIY chocolate, a kind of handmade chocolate with raw materials imported from Spain, with different shapes and colors, and you can write blessing sentences, which is very warm. The cartoon bouquet has the beautiful characteristics of flowers and can be preserved permanently. I believe your girlfriend will like such a unique and innovative combination.