Please understand that this type of question is likely to sound like an XY problem - there’s an exposed column in the interface that’s designed to handle a need, and you’re asking about visibility to something else that would answer that need differently. It sounds like you have a use case/workflow/etc. that isn’t enabled by the current design, so now you’re having to work around a shortcoming in the intended design, or in its implementation. Folks here are going to want to understand if there’s some other underlying problem, then - not to be intentionally difficult, but to try to save multiple future steps down the road.
Regarding a column listing the raw extension after the ., as far as I can tell that already exists, and is accessible from the column selection menu - are you seeing that available on your device?
I do still think it would be valuable to understand what types of tasks are aided by having both forms of that information, since at the very least, there might be something that you or others are using Dolphin for that hadn’t previously been considered and could inform other work in the project.