Theme doesn't stay on even with Package disabler

Hi everyone,

So today I wanted to try out the new Olympics theme. So I downloaded the theme through xda, installed it and disabled theme and theme store as usual. But it seems like in July's security patch, they have blocked this method. Theme still reverts back :( Has anyone found a workaround? I don't want to root my phone yet, so if anyone knows a solution, please let me know

Thanks in advance