@mhaberler Here we are four years later and not even a reply until mine. I have the same request.

@Ondřej-Šutera The request is not to turn off the background map. It's just to turn off automatic switching from the large-scale smooth colored style to the small-scale jagged terrain map. Here are screenshots that illustrate the difference.
https://drive.google.com/file/d/1twns3pZZlBZEVWeyrZ8zCq3rrkIsOgFX/view?usp=drive_link, https://drive.google.com/file/d/1Kx6n1bmPyVuEEf3d4kbrfSZVDDgxjkec/view?usp=drive_link

@Ondřej-Šutera The request is not to turn off the background map. It's just to turn off automatic switching from the large-scale smooth colored style to the small-scale jagged terrain map. Here are screenshots that illustrate the difference.
https://drive.google.com/file/d/1twns3pZZlBZEVWeyrZ8zCq3rrkIsOgFX/view?usp=drive_link, https://drive.google.com/file/d/1Kx6n1bmPyVuEEf3d4kbrfSZVDDgxjkec/view?usp=drive_link

@Ondřej-Šutera Hello Ondřej-Šutera, The request is not to turn off the background map. Rather, it's just to keep the large-scale (zoomed out) style when zooming into smaller scales instead of automatically switch to the very busy detailed map style. Below are two screenshots showing the threshold between the two styles. There should be a way to choose between the two at any (or most) scales rather than automatically switching at a fixed scale threshold. Thanks.

https://drive.google.com/file/d/1Kx6n1bmPyVuEEf3d4kbrfSZVDDgxjkec/view?usp=sharing, https://drive.google.com/file/d/1twns3pZZlBZEVWeyrZ8zCq3rrkIsOgFX/view?usp=sharing

@mhaberler Here we are four years later and not even a reply until mine. I have the same request.