How about gifting them a physical Bitcoin coin or a cryptocurrency hardware wallet? This will show that you have put extra thought into finding a gift that aligns with their interests. Another idea could be to give them a book on blockchain technology, such as "The Internet of Money" by Andreas Antonopoulos, which is a great introduction to the technology. Alternatively, you could consider buying them a stock in a blockchain-related company or a membership to a blockchain group or forum. Finally, you could arrange a meeting with a financial advisor who specializes in cryptocurrencies, providing them with expert advice on their investment opportunities.
Or you can get her/him a star map with the date of the wedding.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.