Although this article from Apple denotes macOS 10.15 Catalina
About the same requirements apply to current versions like Tahoe
All apps from the App Store are signed by Apple. This signing is designed to ensure that they haven’t been tampered with or altered. Apple signs any apps provided with Apple devices.
On devices with macOS 10.15, all apps distributed outside the App Store must be signed by the developer using an Apple-issued Developer ID certificate (combined with a private key) and notarized by Apple to run under the default Gatekeeper settings. Apps developed in-house should also be signed with an Apple-issued Developer ID so that users can validate their integrity.
App code signing process in macOS
Mac app security enhancements
App security in macOS consists of a number of overlapping layers—the first of which is the option to run only signed and trusted apps from the App Store. In addition, each macOS layer adds protection to help ensure that apps downloaded from the internet are free of known malware. Apple operates a threat intelligence process to quickly identify and block malware. Malware defenses are structured in three layers:
So, turning OFF Gatekeepers, if it were possible, kind of Closes that Door regarding " turn off all security permanently "