How to install apps on iOS 14.5 without Xcode 12.5?

I have installed iOS 14.5 but Xcode 12.4 won't install my apps to the iPhone anymore. I need the new Xcode 12.5 but this runs only under Mac OS Big Sur. My iMac is unable to install Big Sur. How can I install my apps to my iPhone?

I started developing in SwiftUI only a few weeks ago and was happy to have my first tiny apps running but now Apple suddenly stops my first steps in coding with this incompatibility. I am not going to buy a new Mac only to have Big Sur running. Is this Apple's way to say "Everyone can code"?
How to install apps on iOS 14.5 without Xcode 12.5?
 
 
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