Is it permissible to pay the Zakat for land, which was estimated at 3,000, by purchasing household furniture and giving it to the maternal uncle who is known for his poor management and squandering of money?

The categories for Zakat (definition) expenditure have been clarified by Allah Almighty in His Book. There are eight such categories, and one's obligation is not fulfilled except by spending Zakat within them or in one of them. If your maternal uncle is among them, then it is permissible to give him Zakat. The fundamental principle is to transfer ownership of Zakat to the poor person so they can dispose of it. However, if they are imprudent or a minor, it should be handed over to their guardian. It is permissible to disburse its value (money) out of necessity or for an overriding benefit.