Monitor blinking

The problem started 1 week ago.

When starting the PC, everything works perfectly except by the monitor blinking.

The entire screen turns off (the white display light goes off) and turns back on 1/2 seconds later. Windows works normally during this problem, you can briefly see the Desktop, it's just the screen that keeps turning on and off.

I tried removing and reconnecting the HDMI cable, still the same thing.

I tried to put it on the motherboard port, it doesn't give a signal.

I thought it might be a driver problem, so I tried to open the BIOS when starting, but the BIOS screen still 'blinked'.

The only solution I found is to restart the PC until it work. When the monitor stays on, it works perfectly for hours and hours, without any problems. Until I turn off the PC and try to turn it back on again.

Now this makes me think the culprits are the video card, monitor or the cable.

If anyone has any idea what is going on and can shed some light on it, I would be very grateful.

The monitor is not new, which reinforces the idea that it is a problem with the monitor.
What bothers me is how specific the problem is. After it turns on permanently (after a few reboots), the monitor works perfectly for hours.
At first I thought the problem was the cable or the HDMI connection, but this would cause the monitor to have problems during use (I believe).
Another detail is that this happened for the first time 1 week ago, but a whole week passed before it happened again.
My biggest fear is that it's a GPU issue. Would something like that make sense? As I said, Windows works perfectly even when the screen is flickering.
Anyway, I'll test another monitor on the PC this week, just to be sure.

I tried this. Disconnecting and reconnecting the HDMI cable, nothing changed.
As for turning the monitor off and on, I need to test better next time, I tried turning it off just once and didn't work, I have to try turning it off multiple times.

Just a quick update, I'll probably only be able to get another monitor to test on Wednesday, but while I was looking for more solutions, to my surprise, I came across a video that replicates the problem exactly. The person in the video is speaking in Portuguese, but in a quick translation, he says he removes the cable so the screen 'heats up' with the image of the lack of signal, and after a few seconds he reconnects and the monitor works.

I don't know if it makes sense, but it fits with my solution of restarting the computer, as the same screen appears when I turn it off.
Theories aside, in the video description he says that he fixed the problem by changing the power cable. I still have to test this hypothesis, but it seems like a simple solution.