GE Smart 3-Way Switch

I have a hallway with a single light. It can be turned on and off by either of 2 switches which happen to be at opposite ends of the hall. I bought a GE Smart Switch as well as the Add-On Switch. I wired the main switch up exactly like directed. When I got to the Add-On switch, this is where things were different from the “standard” setup. In the guide I watched, the guy had the ground, a bundle of neutral, 2 black, and a red traveler. I only had the red travel, ground, single black, and a single white. I wired up what I could and left the black undone. In the video he bundled his 2 black together and bundled the included neutral jumper with the neutral bundle. I couldn’t not get the light to work from either end. Here is how I have mine:

Main Switch:
-Line going to Line slot (voltage tested good)
-Ground to Ground
-Neutral jumper going to bundal of neutral in box
-Red Travel to Travel Slot
-Black Load to Load

At this point I initially tested the switch before touching the other switch to see if it worked, it didn’t. I know these switches are wired different than dumb switches so I figured that was the case.

Secondary Switch:
Ground to Ground
Red Travel to Travel
The one and only Neutral to the Neutral slot
Black Load currently not connected to anything. In the video it was bundled to another black which I don’t have.

Any advice would be appreciated since I’m not sure where to go from here. The Add-On switch doesn’t have anymore usable slots.

Are these the only switches in their respective boxes?

If I’m understanding correctly, this means you have three sets of wires (Romex lines) coming into your main switch box and one set of wires going into the secondary switch box?