Have you seen the 2 function in the file menu to create playlists?
Use these on a list that you have created with a filter like
%origyear% IS 1984
You find more on filters in the documentation:
my solution is then a cross between your reminder of the filter function and the .exe from Dano (topic Dano - Splitter)
I filter my whole database then export with an adapted export file (it's a loop from folder with an inside loop from %origyear% or %Itunepurchasedate% depending on the %_extension%... fuuuuuuuuun )
After that, the result is splitted in multiple playlist (m3u in my case).
In my case, the goal is to create playlists according to purchase dates.
The purchase date is in the %origyear% tag.
There are however 2 other cases: m4a (%itunespurchasedate%) or a file for which I no longer know the purchase date.
Before starting, I fill the empty %origyear% with the action: