1. You can try to ask him out for a candlelight dinner. In the past, it was always boys who gave flowers to girls. Now it can be reversed. Isn't it fresh for girls to give flowers to boys? The Doraemon cartoon bouquets that are very popular on the Internet are very suitable for men. You can consider giving him a surprise.
2. For birthdays, if conditions permit, it is best if you can make a cake for him by yourself, which can definitely show your heart. Then give him a flower, choose a box of exquisite handmade blessing chocolates and give it to him, which will probably be very touching.
3. Birthdays are usually celebrated by having a meal, singing songs, going to a nightclub, etc. It is also okay to celebrate alone. You can watch a movie together, invite him to your home for a meal you made by yourself, etc.