You don’t have to pay for the game! The game is free for everyone to play!
The price is optional; Instead, you can download it by clicking this link (as indicated below).
The database has a limitation to desktop builds so it might not even work properly. Maybe using an Android emulator fixes the problem?
You can read this issue for more information about this problem: Issues_with_Firebase_in_Unity_Desktop
https://drive.google.com/file/d/1gTBn_JMSAVaWNkd_8OsE86F40QInsGTm/view?usp=shari...
I did a recording of my screen to lookout about the thing I mentioned