Hi Diego,
Survey123 does not currently support the .tpkx format, we only support the original .tpk format. We are working on supporting .tpkx in both the Basic and Standard map type option in the future, as it requires changes to both Connect and the field app, as well as changes to the underlying plugin that displays the maps.
Is there are reason why you needed to choose .tpkx over .tpk, can you try to save the tile package as a .tpk (not .tpkx) and then Survey123 Connect and the field app will be able to display it using the Basic and Standard map type option.
Regards,
Phil.