I used the Enhanced Speech on a clip in Premiere and the result I got back is unusable. I then sent the audio to Audition, so that it would create a WAV file from the MP4, restarted Premiere, re-processed the new file with Enhanced Speech, and got the same result.
I then took that WAV file and uploaded it to the Enhance Speech on the Adobe Podcast website and it worked like I expected it to.
I am on a 2020 i9 iMac with maximum specs (2TB SSD) and macOS Ventura 13.6.6.