You may not have a compatible device. Call of Duty Warzone Mobile requires a device with at least 2GB of RAM and 3GB of storage space. You may not have the latest version of the Google Play Store app.
If you're signed in but having trouble connecting, check your system's status page for connectivity alerts, maintenances, or other factors indicating that servers are not fully operational. If there are issues with your system's servers, you might experience connectivity issues until they return to full operation.
Are there any games that actually pay real money? Yes, there are many apps that pay you real money to play games, including apps that use the Skillz competitive gaming platform. If you're wondering how to make money on the side, games that use the Skillz platform could be a good place to get started.
None of them. As you've discovered, NOBODY is paying you big money just to play games or watch videos. Feel free to play those games if you find them fun (some people do) but do not play them expecting to ever get paid.