Should I investigate and inquire about the source of the funds of the company I work for, and whether my salaries and dues are paid from usurious profits, especially since I am not certain of that?

Working in companies or institutions engaged in permissible activities that also deal with riba (interest) is permissible, and the earnings from it are lawful, provided the worker is far removed from the usurious transactions. Sheikh Ibn Uthaymeen was asked about the ruling on working in a company that deals with banks using riba. He replied that as long as the employee does not write riba contracts, nor witnesses them, nor takes them, nor gives them, then there is no blame upon him, and his work is separate from riba. Based on this, as long as the company's work is permissible and the worker is not directly involved in usurious transactions, his salary is lawful, and he is not required to investigate the source of the salary.