Will Allah accept the repentance of someone who worked as an accountant in a foreign company and committed financial violations such as manipulating reports and deducting amounts for himself without anyone's knowledge, then regretted and repented, knowing that the money he acquired is intertwined with his life?

You must initiate repentance to Allah by returning what you took unjustly to its rightful owners, or by seeking their forgiveness. As for the money you earned from investing the unjustly acquired funds, the preponderant view is that the profit should be divided between you and the owner of the money, as Shaykh al-Islam Ibn Taymiyyah held. The principle is to return the right to its owners immediately. If you are unable to do so, then return it according to your capacity, while spending on yourself what you need for your sufficiency. If you do this, then your repentance and worship will be accepted, Allah willing.