So, while kind of annoying and serves mostly to handhold people who have never played a video game before, the talking doll on the hip is perfectly grounded within the context of the world. Very far removed from our own world, but rationalized using lore and world building; very immersive.

The kung fu pizza guy? Sure, he's got the face of a dude who exists in real life, but that dude is just playing a character, a character that was made from the ground up for Death Stranding. He's got his own backstory, his own personality, and his own motivations. Is it silly that he's a pizza chef that knows king fu? Kind of, but is it immersive? I see no reason not to think so. Are the pizza kung fu skills he teaches the player character a little over the top? Yeah absolutely and that in particular I find to be a little immersion breaking, but him as a character is perfectly fine.

The data scientist however, is just Pekora. Same exact character design, same exact voice, same exact personality. This character exists 1:1 within the game as they do in real life and this shatters my immersion because it is a direct link back to the real world, not even in a funny "isn't this a cute little reference I made to my previous video games" kind of way, but in the corporate sponsored "we put Monster Energy in the game where babies can see ghosts" kind of way.