@vmsman - great write up, I was able to follow it and get the server running on my Linux box. I didn't use LXD container (not familiar with containers), but was able to install the nodejs, npm and started the index.js.
Everything went pretty smoothly until I got stuck on the Amazon login (as you indicated), I ended up just stopping then restarting the index.js and then re-tried the Amazon login... and it worked.
sudo pm2 stop index.js
sudo pm2 start index.js
I mainly use Echo Speaks for controlling devices that only integrate with Alexa and not Hubitat. I use the "Voice CMD As Text" option and create routines in HE to control these Alexa only devices... and have become dependent on it.
Anyway... So happy to have my own local server and be free from Heroku, thanks again!