Is it considered a sin to spend on luxuries or on relatives and family, given the existence of debts and dues to others that will take a long time to repay?

It is not permissible to donate or give charity from one's wealth before fulfilling obligations [paying off debts]. One can inform their family of this. It is advisable to supplicate to Allah for the repayment of debts. Among the well-known supplications is: "O Allah, I seek refuge in You from anxiety and sorrow, and I seek refuge in You from inability and laziness, and I seek refuge in You from cowardice and miserliness, and I seek refuge in You from being overwhelmed by debt and from the domination of men."