Strength of schedule is an overrated measure. Things can change so much team to team that previous year's performance is not a great indicator of future performance.
what you say is true, but this is in general terms.
Teams that were bad last year will still probably be bad, and same for the good teams.
There are the exceptions each year though.
This SOS deal is probably base on wins and losses from last season and whether you play a team at home or on road, and also
how good were your div opponents last year in wins and losses.
It is just in general , it wont be totally accurate.
Also dallas had 2 very weak teams, so those team will not be considered to be hard games by anyone right now.
NYG and Wash, if fans here predicted those 4 games right now most will have dallas winning all 4.
Some might say a split with wash.
One thing that has helped dallas be 12-5 is winning those 4 games each year.Wash did win one in 22?