Does the XS package offer access to all channels?

No, the XS package does not provide access to all channels.
The XS package is the entry-level tier of the “Entertain Me!” option and allows you to choose one à la carte channel from a specific selection.

To access more channels, you need to opt for higher tiers (S, M, L, XL, MAXI), which allow you to select a larger number of à la carte channels.