Split field name of feature class in ArcGIS

Is it possible to split a field name within an attribute table of a feature class into two new fields where just the field name is being split. Please note that I do not need to split the features (rows), just the field name.

So for example, I have a field name called "JoinCount_5meters" and I would like to split this field name into two new fields called "JoinCount" and "5meters". Again, the features themselves (row values) do not need to be split. so, anyone have any ideas how I could split a field name into two new field names in ArcGIS?

I understand I can do this manually but I have 250 feature classes for which I need to split 16 field names in each feature class. It would be great if I can do this process using Python or within model builder using an iterator.