Universal Containers wants to control the visibility of a specific section of a Lightning page...

Current Salesforce functionality makes D. Dynamic Forms the appropriate declarative answer. Lightning App Builder supports visibility rules on Dynamic Forms Field and Field Section components, and Salesforce specifically documents device-based visibility through the Device context. An app builder can therefore configure a section to appear for the required form factor, such as phone or desktop, without developing a custom Lightning Web Component. Record Types determine business processes, picklist availability, and layout assignments; they are not device-detection mechanisms. Traditional Page Layouts likewise do not provide device-specific section visibility. A custom LWC could implement custom form-factor behavior programmatically, but it is unnecessary when Dynamic Forms provides native declarative visibility controls.

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