Full suspension bikepacking. can it be done?
There are rear racks such as the Thule Tour Rack which attach directly to the “seat stays” or fork of a full suspension MTB:



I’m not an expert on MTBs and don’t own one myself, but apparently a disadvantage of this solution is that it makes the luggage part of the unsprung mass which should be as small as possible. However since you are probably not riding demanding trails with 20kg of luggage attached I doubt it’s going to be much of a problem.