Help: Grey glitches in darker areas

I'm rather new to Davinci/video editing in general and I have tried multiple ways to try and resolve the issue but nothing seems to work. When the video is exported or on playback in timeline, there are these grey pixels here and there that last for a frame or two. Is there any reason why this is? I am using version 18.6, intel core i5, intel iRISXe graphics.

Do you only have the iRISXe graphics? That wouldn't suffice for DR.

I do only have the iRISXe graphics but the thing is, I have edited videos before this in DR and there were no issues at all.

Nevertheless, that project or any specific setting may have driven your GPU over the edge.
If you could share a small archive, others can see if it replicates on their hardware.
Or you could try another codec, like DNxHR, if you didn’t yet.

I'm rather new to Davinci/video editing in general and I have tried multiple ways to try and resolve the issue but nothing seems to work. When the video is exported or on playback in timeline, there are these grey pixels here and there that last for a frame or two. Is there any reason why this is? I am using version 18.6, intel core i5, intel iRISXe graphics.

My guess is the GPU is very weak and is getting overloaded and stressed out, and just can't handle the material. I'm guessing this is highly-compressed H.264 8-bit video?

I'm rather new to Davinci/video editing in general and I have tried multiple ways to try and resolve the issue but nothing seems to work. When the video is exported or on playback in timeline, there are these grey pixels here and there that last for a frame or two. Is there any reason why this is? I am using version 18.6, intel core i5, intel iRISXe graphics.

My guess is the GPU is very weak and is getting overloaded and stressed out, and just can't handle the material. I'm guessing this is highly-compressed H.264 8-bit video?

I'm not quite sure. I filmed it on my iPhone 7s which I recently upgraded to iPhone 12. It says it's in HEVC format.

That's H.265 and even harder for the GPU. But the iPhone should offer a compatibility mode.l, which is H.264.