If your Google Business Profile uses a hotel-type category, the Google Vacation Rentals integration in Hostfully or Guesty does not apply to your listing.
Why this happens. Hostfully and Guesty are partners for Google Vacation Rentals, a separate program designed for vacation-rental property categories. Hotel-type categories such as hotel, motel, inn, and apart-hotel fall outside that program.
What you can do. The program only becomes relevant if you change your profile category to a vacation-rental type. Changing the category also changes how Google presents your listing overall.