This is amateur advice. You can't lift with your knees for a bulky and squishy item like a body if it's in front of you. If you attempt this, you'll notice that your knees get in the way and you need to reach out a lot and can't lift as a result. Body isn't like gym weights on a perfectly nice to grab steel bar.

If you don't actually have to lift at all, just drag it. And if you do, use a fireman's carry which is designed for carrying unconscious hoomans.