Select one track or file > Analyze > Contrast > Measure Selection.
Write that down.
Measure the other one.
Contrast will give you the RMS or overall loudness of the performance. That’s not the final word because that doesn’t take into account tonal differences, but that’s the way audiobooks measure general loudness.
You can also open both performances and select one at a time and measure Forground and Background.
I’m a little foggy on what you actually did. It should be possible for you to switch between two microphones. Are you recording a good microphone and then both? You can sort what you’re recording by scratching the microphones.
You have all the problems that performance actors do. Don’t do the test in a “live” or echoey room. You’ll be analyzing your room in addition to the microphone. I had access to a small movie theater (screening room) with very few echoes and almost no noise.
Fair warning if you’re using the Mic-In or Headset connection on your laptop, that has 5 volts DC on the connection because “computer microphones” need that. That can mess up a home microphone design that doesn’t need it.
Ideally you would use an audio interface that has two identical microphone inputs so that you can record one mic on the left channel of a stereo track, and the other mic on the right channel. You could then use a variety of tools that are available in Audacity to compare the two channels (for example: “Plot Spectrum”: https://manual.audacityteam.org/man/plot_spectrum.html)