Question display black screen

Jun 13, 2020
hey, I have a LG 24MP48HQ-P monitor, in the past days it had a problem of the screen going black for a few seconds, over the days it got more and more frequent, I was suspecting it's the cable, because it's barely long enough to plug in and at the ends it's a really tight fit and I was thinking the cable is strained. At the same time the windows shows that there is a second monitor connected (I use this as a second monitor) and when I unplug it, it disappears.
Now I think it's the power supply, because when the monitor is connected to the PC its indicator light is slowly flickering as if it can't provide enough power, but when it's disconnected it shows everything correctly (like no input detected/going into sleep mode). I was reading about other people's issues and many of them talk about the power supply, but I'm unsure.
All in all I know close to nothing about monitors and I base my suspicion on what others have said, I think there are people who know a lot more about displays and I'd like to hear what they think my problem might be, it would help a lot to know what to look at and where to start.