Is it permissible to borrow with interest (usury/riba) to pay off debts and pressing living expenses, given the inability to borrow from other sources?

Usury (riba) is not a solution, and it is not permissible to resort to it except in cases of dire necessity, which is not present in what you have mentioned. Creditors should grant you respite until you find ease. You can seek permissible means to overcome your situation. We advise you to supplicate frequently, especially with the supplication reported from the Prophet, peace and blessings be upon him: "O Allah, I seek refuge in You from anxiety and sorrow, and I seek refuge in You from incapacity and laziness, and I seek refuge in You from cowardice and miserliness, and I seek refuge in You from the burden of debt and from being overpowered by men."