Look here for Gutenprint downloads then look a little further down the page for Printer Drivers. You have to look carefully at the lists of supported printers as the Gutenprint (formerly GIMP Print) drivers are often backward or alternately compatible with any number of different models.
I used to use Gutenprint in preference to OEM drivers because they were better and often supported features not supported in the OEM drivers.

32 bit drivers will still work in Mojave (I have three or four I am using because the vendor has not yet updated their MacOS driver to 64 bit) but they are still being built and the vendor will have to update before MacOS 10.15 Gutenprint is very actively supported so I am confident that if it isn't 64 bit now, it will be in time for MacOS 10.15.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein