How to change scaling

I have a 2020 M1 MacBook Air. When I connect my external 1080p/32" monitor in mirroring mode, via AirPlay, my scaling changes. I like this scaling very much, it is much more usable for me than the default scaling options in System Preferences. How can I force macOS to always use this scaling without connecting to a second screen? I have already tried scaling options in System Preferences → Displays and set it to "More Space".