Keep in mind that this display as well as some of LG’s other higher end ultra wide displays have firmware that with a compatible (and compliant spec wise) host system allows things like appearing to the host OS as two separate displays.
That allows for instance a bit less hassle in trying to run multiple apps without futzing with things like Windows “snap to” which good as it generally is, is optimized for more standard display resolutions and aspect ratios. In this monitors specific case, older intel integrated graphic chipsets such as those in core I 10th gen.
OTOH, the “custom” functions can also confuse especially non Windows systems , which is likely why iPad Pro/IOS 16/Stage Manager seems to be a no go at present. However we’ve heard unofficially that LG is working on an IOS app to manage some of their more esoteric displays with an iPad, something that wasn’t possible prior to IOS16.
PS: Why it works on Windows is related to device enumeration (aka plug and play/pray) which on IOS is new save for support several common display aspect ratios and resolutions such as Full HD (1920x1080).