I found a question from almost a year ago about splitting a string into and array of substrings.
This was suggested as the solution by yoshihirok and v-micsh-msft:

I have since attempted to set up a flow with identical parameters and it fails, it appears to not be actually splitting the string but
passing the whole input in the compose action. Here's a shot of the error I get.

Is there some sort of formatting error with my JSON? When I set it up to just blast me an email with the output it sends me "@split('Hello #a1',' ')"