Dezzmotion

Hello , i hope you can help me. So, i recently bought a new case (Sharkoon RGB lit 200), but because the 8-pin CPU cable and the 24- pin cable were too short i wanted to order extensions. But because they took so long to arrive and i needed my pc for school work, i soldered extensions in the cables. When i was finished, i moved everything to the new case and plugged the cables in and started the pc. All the fans started spinning and the LEDs lighted up, but no signal on the monitor. Also keyboard and mouse werent lighting up, but the ez debug cpu led lighted up. So i thought that was because of the cables (although the 8-pin CPU cable was 100% correct) and decided just to order whole new longer cables. They arrived yesterday, but still the same problem. I reseated and checked the cpu, the ram, i tries different ram positions but nothing helped. I also tried clearing the CMOS. Can anybody give me some advice? I'm pretty frustrated at that point. My specs: Mb: X570-A Pro Cpu: Ryzen 5 3600X Graca: Zotac Geforce RTX 2070 Mini Ram: 2×8GB Corsair 3200 MHz DDR4 Psu: be quiet SFX L power 600W SSD: Samsung 970EVO 1TB