Ronan,
I was the guy that posted the limiter circuit back when. Here is a link to it:
No, it does not distort until levels get quite loud. This is essentially the same as what the telephones utilized for nearly a century so nothing new.
I did publish a simple RF AGC circuit in January 2021 page 33 (since improved) but is not applicable here. Hans will eventually implement AGC in the QMX as a superior firmware feature. This is a true Software Defined Radio and the audio processing is entirely digital, making Automatic Gain Control just a software code entry. Values beyond a selected level are simply re-mapped to provide low distortion compression. Just like Flex and the other "Big Boys" do.
In the meantime, you might try an external jack (if you don't want to use a speaker) with the resistor and limiting diodes. It's cheap and effective. Try it yourself and see if it works. There will always be naysayers and detractors but I always advocate trying something just to be sure. Especially something so simple and cheap. Pennies really.
It's a hobby. Have fun!
72, Don
Don, ND6T