I need to factory reset my phone but I'm afraid to because I don't know if my worlds on Minecraft PE beta will still be there when I re download everything. I used an apk to install it.
You will lose them but there is a way to keep them.
You will need to download your worlds on an external drive. First you have to find the file location. In your files app go to:
Phone > Minecraft > com.mojang > minecraft_worlds
All of your worlds will be listed here. Now take each world and compress it into a zip file (you have to do this). Move the zip files to your external drive. I recommend putting them in a folder for organization.
Do the same to resource and behavior packs of you want to save those as well.
You are now free to factory reset your phone.
After you factory reset redownload Minecraft and go back to the minecraft_worlds file. Then put the zip files in and unarchive them.
Your worlds will now appear in Minecraft. Hope this helped :)