(sorry for the late reply, been a hectic week)
Would you be able to provide a build?
https://drive.google.com/file/d/16tU_WJbNLCHJ8NiP1uGV3RA-jXnjSULf/view?usp=shari...
If it works for you, you should see a red sphere in the middle with the whole camera having the JPGPU filter.
If it doesn't (like on my PC) it will seemingly freeze after the unity logo.
Another thing to note is that your demo of JPGPU ( https://ompuco.itch.io/hlwl ) works fine when I test it out in my web browser.