Accessing Nextcloud with

I’m trying to use the Ulysses markdown app with my nextcloud through its external files feature, but the Nextcloud files provider doesn’t work with it, presumably because it mainly works by only showing individual files as opposed to providing a whole folder. Are there any clients out there that could work with Ulysses and nextcloud? Or could someone possibly give me an explanation as to using the “local” external storage feature that would make it work with an Apache installed version of Nextcloud?