Can't find Photoshop Beta on my Mac

Hey, ​@HALF89. Welcome to the Photoshop Community. I'll need more info to help you figure this out. I've checked the account you've used for Community & you have an active subscription. 

Is this a personal machine, or does an IT team manage the device?

Try this: 

• In the Creative Cloud app, press CTRL + ALT + T (Win) to launch Creative Cloud Troubleshooter & select 'Close Creative Cloud and related processes' > click on Go. 
• Open the content here and select the blue ‘Get Started’ button: https://helpx.adobe.com/in/photoshop/desktop/whats-new/whats-new-in-photoshop-beta-on-desktop.html
• Allow the browser to open the Creative Cloud app. 

Let me know how it goes. Thanks!
Sameer K