What is the permissible and most suitable method for obtaining a loan from Al-Ahli Bank, and what is the ruling on the previous loan the questioner took, which was through the method of Tawarruq with the bank being appointed as an agent to sell the commodity?

There is no sin upon someone who engages in a transaction that has been declared permissible for them, even if it later becomes apparent that some scholars deem it forbidden. The layman's school of thought is that of the one who issues the fatwa to him. The tawarruq conducted by banks is not all the same; some of it is permissible, and some is forbidden, which is known as organized tawarruq, because it is a trick to circumvent usury. The Islamic Fiqh Academy has issued a resolution prohibiting it.