I ended up tinkering around and found I needed to use the os package to access it as a '/dbfs/' filepath:

#Iterate through directory of docs, load, split then add to total list

txt_ls = []

for i in os.listdir(dir_ls):

    filename = os.path.join(dir_ls, i)

    loader = TextLoader(filename)

    documents = loader.load()

    text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=0)

    texts = text_splitter.split_documents(documents)

    txt_ls.append(texts)