To convert from epoch to something human readable, you can use the Javascript Date function, like this:
var convertedDate = new Date('1650550779577' * 1000);
If you output the convertedDate variable, you'll get something like this: Fri Nov 14 54273 15:39:37 GMT-0800 (PST)
You can then use qie.formatDate() to change it to whatever format you want, like this:
var formattedDate = qie.formatDate('yyyy-MM-dd HH:mm', convertedDate);