Why eat pizza with anyone? Just eat it on your bed by yourself.
The thing I get from Shinri is he seems like a pretty touchy feely kind of guy and tends to focus on internal and personal emotions, he likes looking inwards on a more emotional level and expressing himself that way likely due to the upbringing you cited. So how well you vibe with him probably depends on how well you can understand him I think.
Like for example, his second zatsu he talked about photos and how he likes to be behind the camera because it helps me align with that memory, which makes sense because his memory is garbage and in his brain the physical memory of taking the photo alongside the scene itself helps him remember. I have some pretty rough memory issues so I could really vibe with him on that level, especially when he explained how he "organizes" his room and how he forgets things until he sees them again. He feels like he appeals to pretty emotional people who want to either find someone who understands what they go through, or those who enjoy receiving people's emotions to understand other people.
Vesper I find is far more analytical and looks beyond his personal feelings while having a lot of personal stories he goes into, while Shinri seems to be almost the opposite he feels like a more abstract Vesper if I had to put it simply from these few hours I've seen him solely talk.
Regarding him talking about the game he played last night I'd imagine that he probably meditated on the game and his experiences with it which is why he talked about it after playing it and not during it, which makes sense for someone like him who seems to like to reflect on his emotions and then express them. To my understanding from the handful of clips I've seen of his horror stuff, he tends to casually talk about other things as he plays too, as opposed to focusing on the game. This man feels like an almost 24/7 zatsu while he's on stream from what I can tell due to what he plays and how he plays them where he just chatters on and on. Man shows little fear at all, so it is easy for him to just talk forever.
He feels radically different from Vesper beyond the fact that he's older, I can see how he appeals to people but it seems to vary on how much you can unironically vibe with him. Vesper is also much funnier by himself I feel, his voice just works better for comedy while Shinri's voice is too deep and soft unless he's being a smartass like in the Ultimate Chicken Horse collab.
