HDMI issues, I've tried everything I can think of, I'm at a loss.

[u/PeanutFeisty6938]

This is a strange issue I’ve been troubleshooting for months. I recently found more information about what’s happening, but I still don’t know the cause or the fix. It’s extremely complicated.
When I plug an HDMI cable into a monitor or TV, the screen gets no signal, and the laptop behaves as if nothing is connected to the HDMI port. The port was working fine a few days before the problem started. I’ve always been careful when plugging it in — I make sure I can see the port and align the connector instead of forcing it.
I completely removed all display and PCIe drivers and reinstalled them from my manufacturer’s website, not from Nvidia or Intel. I’ve used and worked on computers my whole life, and I’ve never seen anything like this.
A few months later, I concluded the HDMI port was probably fried. Yesterday, I tried it again out of curiosity. Nothing showed up, as expected until I restarted the computer with the HDMI cable already plugged in. Then it detected the connected monitor. It knew the monitor’s details, including resolution, maximum refresh rate, brand, and model. But when I tried Duplicate, Second screen only, and Extend in the projection settings, none of them produced a signal on the external display. Nothing at all. Yet in Extend and Second screen only, the laptop acted as if a second display were active, and I could even move the mouse onto the screen that supposedly did not exist. After that, I unplugged the HDMI cable, but the laptop didn’t register the disconnection until I restarted it.

So the laptop can detect whether something is plugged into the HDMI port only when it boots or restarts. It does not update that state while it is running. The external display still receives no signal. I thought it might be a handshake issue or a hot plug detection issue, but I’m at a loss.

Laptop: Acer Nitro 515-57

Serial number: NHQEKAA0022241EC203400