Tbh, I've been wondering about how stable subtypes might be. Maybe I'm just unstable.
I was thinking on the many times I took a single test over time and mostly got the same type with differing subtypes. I've seen 0,1, and 2 on both side. I don't see myself as having a set subtype's what I mean, tho I think some people somewhat do.
I'm more one to think a pronounced subtype is bad news no matter where it leans, it's closer to a painful adaptation imo.
What do they look like? Too much, stuck in a certain way/mentality, less flexible.
I guess there's a difference between having a subtype and living a life or being in a setting where one ego function is more required than the other. There's a lot of context to consider.

Considering IR, well, my most used function's Fe, like most peeps where I live, and it's not in my ego so idk. Cultural phenomenons can mess up IR for those whose ego functions aren't part of the culture.