How to abandon one 3way switch and convert the other end of the line switch to put in a smart dimmer?

I am a fairly savvy DIY and am perplexed on how to proceed. I want to remove one 3 way switch with a red, white, black and ground. I am assuming the white is a neutral, but does not appear to be part of my bundled neutrals in the back of the box. When I tie my red and black together and cap off my neutral, then install my new switch at the end of the line box, my new switch does not work. How do I remedy this? In the box I want to keep, I do have a red, black, white as well along with a ground.

First photo, the switch I want to remove, bundled neutrals in back right of box.(https://i.stack.imgur.com/KGDVY.jpg)

Second pic, box I want to retain, currently connected to a Lutron Diva Dimmer, no bundled neutrals. (https://i.stack.imgur.com/nrZuM.jpg)

First switch with better lighting.(https://i.stack.imgur.com/ulEnr.jpg)

First box again with incoming Romex(https://i.stack.imgur.com/A6IIJ.jpg)

Wiring of switch I want to nix (https://i.stack.imgur.com/DYZAR.jpg)

Other side of switch wiring (https://i.stack.imgur.com/ZhCO9.jpg)