Here is my Alexa configuration. I am have an Echo Show 5 and an Echo Input. My feeling is that verbally asking Alexa to scan for new devices works better than attempting to scan from the app. Works flawlessly for me.
module: 'MMM-AlexaControl',
position: 'middle_center',
config:{
image: false,
deviceName: "Mirror",
pm2ProcessName: "MagicMirror",
vcgencmd: "wlr-randr",
},