In my setup, the line box has the line connected through (blue box, wire with nut) to the further switch. It powers two separate light groups (red vs yellow). There is only a neutral in this box, not in the further one.

Looking at the red setup, the red wire in the blue box is going to the further switch.

The yellow setup for uses two line wires but only three show up at the further switch.

Could anyone please advise on how to change/use this setup so I can use the line in this box with the neutral?

Thanks!