Db is often my trickiest person to buy for. He is 40, lives in London with partner but no kids by choice. He has more money than me and tends to buy what he wants when he wants it. He has often clearly not been impressed by presents I've given.
Some previous successes have been homemade booze, a case for a hobby item and tickets to an escape room.
Failures have been any books or dvds (he only reads on his kindle and streams films), a cycle emergency kit (he is quite a serious cyclist though), clothing items or food items.
Budget is around £30 but I would go up to £50 if I thought he would really like it.