Unfortunately, the default screen recording feature on an iPhone does not allow for direct resolution adjustment. This means that the resolution of your screen recording will match that of your device's screen. While this ensures clarity, it might not be ideal if you want to record at a higher resolution.
To overcome the limitation of native screen recording, consider exploring third-party apps available on iOS, Mac OS, and Windows platforms. These apps often provide additional features, such as adjustable frame rates, resolutions, and codec options, allowing you to fine-tune the video quality to your preference.