Hello. I have been scratching my head for a couple days trying to get Alexa to recognize a control system I am building to run a set of patio heaters I just installed. I would set up the dashboard and variables I wanted, compile and do an OTA update, but Alexa would not see anything. What I was doing wrong was using just normal datatypes for my system variables, specifically booleans for the switch setting and an integer for the level of heat I wanted. There was a now-closed forum post on here last year where someone was experiencing the same problem I have been having in that Alexa would never see my devices after the compile and load.
What I discovered is that even though when I created the variables and selected "Alexa Compatible" the IDE was simply turning off Alexa compatibility when I hit the save button. That was the problem. In order to get Alexa to recognize the "thing" it needs to be something like a "Cloudlight" or "Clouddimmer." So if you are running into this problem where Alexa does not discover your device, try changing your datatype{s) to one of the cloud-type variables, compile and upload the sketch and THEN do a device discovery. Best wishes!