How to fix my Dell s2719Hc Display?

My monitor gets powered on and is okay from this matter but the problem is that it does not display anything on the screen only black screen, not even the display configuration UI. My technician said it is a motherboard problem and the motherboard cannot be fixed and you need to replace it.

Please tell how I can fix it or if I should get a motherboard part and replace the old one and suggest suppliers or sellers.

But I really want to fix it by myself if it is fixable