Car has been broken up, insurance has conditions

Hello dear ones, now I would like to try myself as a questioner and ask for advice. My car was broken up and the side window was destroyed. In the car were objects worth about 300€. I called the police and then reported to the insurance company. Schroffer Ton, quite different from what I wanted to insure the vehicle… My things in the car that are not part of the car are not insured, so stay at the expense (have no legal protection etc.). B is 150€. I get the disc used for 100 and can do it myself. But the insurance does not pay if I arrive with an estimate. They pay, but only if I have it done and call them the workshop, this should then put the bill to the insurance. But for me this is also 150€… My idea: Win-Win-Situation A workshop takes 600€. So the insurance pays 450€ and I 150. My offer to the insurance: I make it So for insurance 100 and for me 0. Is this going to work? Do I have the right to get the money only with a cost estimate and can I then think for myself if I have it done or screw it myself? I am happy about advice