My phone's screen blinks and then turns off.

My phone suddenly started restarting and then screen turns off (but phone seems to be on as navigation buttons’ light is still on). I then restarted my phone a few times, but it didn’t restart (or I don’t know as screen was still blank but buttons were lit).

I managed to restart it in safe mode, and factory resetted it. After that too it was same (screen off, buttons on). Then I managed to turn it on, but then screen started blinking, and started dimming and after a while, it turned off completely.

(my hunch is that phone is on, it is the screen that can’t maintain it’s power or something. Any help is appreciated. Next thing I am going to try is flash the ROM, but I think it is a hardware issue..