> Everything works just like it's supposed to

There are different defaults for the pane management and the terminal. The vim defaults, IMO, allow a more consistent user experience. E.g. when you are in a vim terminal and you go to normal mode to yank some stuff to put it in the other pane with the code, nvim defaults adds line numbers to the terminal that need to be cleaned up afterwards, vim just does not add them. This is just one small example, but there are several edge cases where the vim defaults behave like I would expect and nvim either does something unexpected or it lags or it crashes.