Create a file called custom-config.js and place it at the root of your web configuration directory…

~/.jitsi-meet-cfg/web/custom-config.js

Edit that file to set/override configuration values like so…

config.enableNoisyMicDetection = true;
config.constraints.video.height = { ideal: 720, max: 720, min: 180 };
// etc.

The content of that file is appended 30 to the auto-generated config.js.