Post Processing with Handbrake CLI w/ Windows .bat

I wrote a windows batch file to convert a file to h.264 codec in a MP4 container. The batch file works fine when I drag and drop a file onto it. It will convert the file then delete the old file only leaving the new one. The problem I am having is when I add the location of the batch file for post processing it never runs. I can see plex commercial removal running in my resource monitor. Once that is done it just adds the file to plex and I can see my library being scanned.

Hoping someone can help me out with why this might not be running.

I have the .bat located on an external hard-drive (could this be the issue?)
Are there guidelines on how to enter the path to the file?

I used drive letter then path, I also tried UNC path but neither worked. Once I get this figured out I would be happy to create a guide with screenshots etc on how to make a basic handbrake post processing script since I see a lot of people on the forums just wanting to compress their DVR recordings to save space.

here is a copy past of my .bat file:

C:\Users\User\Downloads\HandBrakeCLI.exe -e x264 --encoder-preset medium -q 22 --two-pass --vfr --all-audio -E copy -B 160 --enable-qsv-decoding -i %1 -o “%~n1.mp4” -f av_mp4
if exist “%~n1.mp4” (
del %1
)