I hope some of these indeed still exist. These films really appear to be completely obscure even in China. Information about them on the internet is scant.
I also unfortunately get the impression that the bulk of Chinese films from the 1930s and 1940s no longer exists.
However, if even one of these films survives, we could get a look at a completely separate portrayal of Charlie Chan from the 1930s and 1940s.
I wonder if these films are any good at all... They could be really, really bad actually or just very weird and different.
Yet, they apparently made quite a few in this series, so Chinese movie-going audiences must have kept paying to see them!