Amazon (AWS) has made EC2 instances with macOS available. You can remotely run Xcode on it, for example.

In the article on the AWS blog, a new feature is discussed that allows developers to use macOS instances on the Amazon EC2 platform. This capability enables the building and testing of applications for iOS, iPadOS, tvOS, and watchOS in the AWS cloud. It caters to both individual developers and teams relying on the latest Apple programming tools. By leveraging EC2 instances, developers can easily scale the resources required for compiling and testing their apps. This also provides greater flexibility and cost savings, eliminating the need to own Apple hardware. The article concludes by highlighting that such infrastructure enhances team collaboration, supporting projects of varying scales and complexities.