Is Zakat obligatory on an amount of 30 pounds, knowing that the project in which it was invested is not yet complete, and I do not currently possess 750 pounds, and if it is obligatory, is it necessary to borrow the amount, given that there is another debt of 20 pounds?

Religion does not prevent the obligation of Zakat. The amount you paid to your relative to start a project, if it remains as cash or has been converted into goods, is subject to Zakat at 2.5%. The goods are valued at their selling price. As for what was spent on equipping the shop, there is no Zakat on it. If Zakat becomes obligatory upon you and you do not have cash, it remains a debt upon you until you pay it, and you can pay the Zakat on the goods from the goods themselves.