The Vision Pro’s resolution when connected to an Intel-based Mac for external display purposes is currently limited to 3K.
Apple has recently published a support document about the maximum resolution when connecting a Vision Pro on a Mac as an external display. The Cupertino-based company confirmed how the Virtual Display feature can run on any macOS Sonoma machine and put out 4K resolution with a Mac with the Silicon chip. However, when connected to an Intel-based Mac, the resolution drops to 3K. It’s worth noting that macOS Sonoma can run on 2019 Mac Pro or later, 2022 Mac Studio or later, 2017 iMac Pro, 2019 iMac or later, 2018 Mac mini or later, 2018 MacBook Air or later, and 2018 MacBook Pro or later.

To enable Virtual Display, the Vision Pro and Mac must have the same Apple ID and have two-factor authentication, plus Wi-Fi and Bluetooth.