My existing smart light switch has two traveler wires, but the new one I bought only has one! How do I reconcile this?

The existing switch has:

• Live
• Neutral
• Ground
• Traveler one
• Traveler two

The new switch has (their diagram):

• Line (hot)
• Load (light)
• Neutral
• Ground
• Traveler (optional for 3-way)

I find the lack of consistency in these terms to be very frustrating! One company uses L-In, another uses Line, and another Live (and I'm not sure I even have that right)

Overall, my big problem is that I can't find anything on installing a 3-way switch with just one traveler. I put in the existing switch, which was easy enough to find instructions online, but I can't find anything on this.

I've added both diagrams from the switch packaging here: https://imgur.com/blAcXci

Thanks for any help you can offer!