What is the ruling on working for a halal company if it transforms into companies specialized in music, knowing that there is a large debt that requires a high salary to pay it off?

If the employer possesses only unlawful wealth, then it is impermissible to deal with him or work for him. However, if his wealth is mixed (lawful and unlawful), then it is permissible to work for him, though disliked (makrooh), provided that the work itself is not unlawful or an aid to the unlawful, and that the wages are not taken directly from the unlawful wealth that pertains to the rights of others. If continuing in the work leads to directly engaging in an unlawful act or assisting in it, then one must leave it and search for another job, even if at a lower salary.

If you are in debt and fear harm from the creditor, such as being sued or imprisoned, upon leaving the job, then you may remain in the job out of necessity until the harm is removed. This is based on Allah's saying: "But whoever is forced, without willful disobedience or transgressing, then there is no sin upon him" (2:173) and "And He has explained in detail to you what He has forbidden you, except what you are compelled to" (6:119).