I'm not exactly sure how to fix it. I used different project files from the pool party. It shouldn't associate with it at all. I tried installing it on my phone and see the same issue.
It's the problem of the configuration of android APK creating.
I think you haven't change it when trying to create an APK file for this new project.
The configuration is still the one you used for creating the "pool party" you say, so the device sees this project as "pool party", so when installing this, the device will see it as an action of update so then to replace it.
It's simple to fix this, find the configuration section and change it to a different value than the one you are using to build "pool party:
Make sure to note down every configure you typed, because I see you have another project, you'll need to change this value constantly when updating different project.
***I didn't see this project is not made by renpy when replying this, I changed what I'm saying though
But I still think it's the same or at least familiar problem, try to find where to change the configuration of android building***