the elementor widgets are collapsing in width, as they basically scale up / down to fit. You can define a width of the header widget to stop this from happening:
.header-widget {
width: 50%; /* adjust to suit */
}
The header widget only has a max-width property. So the container size is unknown.
Then elementor widgets are set to width: 50%; Secondly they use Flex, without changing the default flex prosperities which includes the element can Shrink.
So 50% of an unknown container size and able to shrink leads to this effect.