KUAL not opening

I believe I have jailbroken my kindle 5 gen. I followed all the process here https://kindlemodding.org/jailbreaking/post-jailbreak/re-enabling-the-store/ . After I finished, I went to open KUAL, expecting to be able to open KOreader. Kual does not open. It says opening... and after a while it goes back to normal, sometimes a blank screen appears for a few seconds, but nothing else.

I installed this: (I believe correctly) https://github.com/KindleTweaks/PEKI . And I still have the same problem.

I am not really tech savvy, so maybe I made a simple mistake I did not know of.

Is there any way to fix this??