If you look closely at the doom argument, it relies on some massive logical leaps and psychological biases rather than actual engineering. Some of it is just barking mad. I read one of the most popular books on this topic last year, and it seriously had a section suggesting AI might be a plot by an ancient demon to fulfill and ancient apocalypse. FFS. It was written by people who otherwise seemed like they'd be smart.
Biggest reason they think this will happen is the omnipotence fallacy which assumes that being incredibly good at processing data automatically equals total physical control over the world. But software cannot magically manipulate power grids, supply chains, or human biology without the physical infrastructure that humans completely control.
Then the doom scenario requires the AI to be smart enough to outwit all of humanity, yet so incredibly stupid that it doesn't understand basic human context or nuance (like the classic thought experiment where an AI destroys the world just to manufacture paperclips, which some people still take seriously, like the idiots who wrote If anyone builds it, we all die, easily one of the worst books I've ever read).
The other major reason is projection. Humans have an evolutionary drive to compete, dominate, and survive. Otherwise smart researchers often project these biological flaws onto code, assuming a highly intelligent machine will naturally want power. They understand machines not biology, so don't realise why we are as we are. A computer program has no ego, hormone drive, or survival instinct unless we explicitly program it to. A lot or people who THINK about AI are not also coding it, or don't understand the wider dependencies. They fall into this basic gap in their knowledge.