SoCalDana The allotted time on the SBB ticket summary
What do you mean exactly by that? From what you wrote, you haven’t purchased a ticket yet, therefore you also can’t hold whatever “ticket summary” yet. You probably simply mean the online timetable, right?
Should you consider a supersaver ticket for the entire ZRH-Vaduz journey (if available), which is strictly tied to the selected train/bus including that 3 minutes transfer in Sargans, then you obviously wouldn’t have enough time for storing your luggage there as you’d need to catch that specific bus with that ticket. So this is the only scenario where you’d need two separate supersaver tickets, if available for both legs at all.
Any other ticket type for that journey, which is either a point-to-point ticket or a saver day pass, will be valid the entire calendar day on any connection. So in this case, after storing your luggage, you could simply take the following bus in Sargans with the same ticket.