Resolution is one of the key factors. For the sharpest results the pixel size of 360 photos used in a virtual tour should be enough that it makes full use of the resolution of the headset’s displays. The Meta Quest displays provide 21 pixels per degree of angular view, so for a 360-degree image to make full use of this it should be no smaller than 21 pixels * 360, or a 7560x3780 equirectangular image. In simple terms this means publishing at 8K – 7680x3840 (8K UHD) to 8192x4096 – in order to ‘fully saturate’ the headset’s screens and show as much detail as the device can present.
Not all 360 cameras will capture photos at this size, so choose your equipment accordingly; it should capture images at a minimum of 7200px wide, and preferably the upper point of 8192px wide. Alternatively, if you shoot and stitch 360 images manually with a regular camera and a dedicated panoramic head you can create very high resolution work including gigapixel panoramas. See Set up a panoramic head to shoot high-resolution 360 photos for details.
Modern virtual tour-building software will convert very large 360 photos into ‘multiresolution’ tile sets so that only the right resolution data is shown as someone looks around. This means a tour will load quickly, look good on a variety of different screen sizes, and even allow zooming in to examine details. But zooming isn’t supported in immersive, headset-based playback, so if the tour is only meant for headset use it is better to resize large source images down to the 8K point that best suits the device. This is normally done before loading images into the tour production toolkit, although some software can do this for you as part of the tour generation step.