Is it permissible to give charity in exchange for a specific benefit, such as purchasing a ticket to an event, knowing that its proceeds will go to charity?

There is no harm in the aforementioned scenario, and the one who performs it will be rewarded according to their intention and financial contribution, due to the generality of the Prophet's (peace be upon him) saying: "Indeed, actions are by intentions, and indeed every person will have what they intended." So, whoever buys a ticket with the intention of contributing to charitable deeds will be rewarded for that.