Giving birthday gifts to middle-aged people requires specific analysis. My suggestion is to choose birthday gifts that he likes based on his hobbies. For example, many middle-aged people like to taste tea, so you can give him tea and tea sets. For example, if someone likes to taste wine, you can give him two bottles of good wine, which can be drunk and placed at home as decorations.
Your uncle is 45 years old and is indeed a middle-aged man, but he has not yet reached retirement age. So my suggestion is to give him some things that office workers can use, such as a well-fitting suit, a tie that suits his taste, and an exquisite watch. These are all good birthday gifts for middle-aged people.
Of course, most middle-aged people like things that attract wealth and fortune. You can choose home crafts in this area to give to your uncle. Not only are they fashionable and generous, but they are also very classy. It is most suitable for people of his age.