So the thing is that platformType relies on what’s called a User-Agent header. The problem is that more and more, browsers have been transmitting values in this header which don’t represent the actual config of the device. For instance, an iPad in desktop mode sends a macOS desktop user-agent string. User-agent string parsing has been discouraged for years because of this.
We have a feature request already to be able to get the device’s screen size before the first page is sent to the browser.
Will that fix your problem?