What is the ruling on giving money to someone in exchange for advice or assistance in completing a task within a tender, if the payment is not linked to winning the tender and does not infringe upon the rights of others? And is it permissible to take a loan from a bank to pay rent when funds are unavailable?

We understand from the question that you intend to give money to a man who works for the entity that issued the tender. If his work is not related to his official duties and is not connected to the tender, and the money is given by your own choice, then there is no harm in it. Otherwise, it is a bribe.

As for the second question, if you cannot pay the rent except by taking an interest-based loan, and you have no other dwelling, then there is no harm in it due to necessity; as Allah Almighty says: ﴿And He has already explained to you what He has forbidden to you, except for that to which you are compelled.﴾