Am I obligated to return money to this man with whom I was a partner, and if so, how much should be returned, and is the usurious loan debt I owe prioritized in repayment, or the partnership debt?

The worker in a Mudarabah partnership is only entitled to the agreed-upon percentage of the profit, and this percentage must be a common one (such as a third or a quarter of the profit). If the entire mentioned amount is profit, then you are entitled to your agreed-upon percentage, and anything beyond that belongs to the capital owner. It is not permissible to take profit without the knowledge of the capital owner. The capital and its furniture belong to the capital owner, as does his share of the profit. If the partner takes anything from that, he has transgressed, wronged, consumed the wealth of another, and betrayed his trust. This money must be returned to its owner, and his forgiveness must be sought. The other debt must also be repaid, even if it is from a usurious bank, without interest, unless you are compelled to pay it, because it is forbidden. As for the creditors, they are all on the same level unless the bank's debt is not yet due. Usurious loans are strictly forbidden.