This season it is a valid reason / excuse. So that makes me think anyone who is definitely travelling to Qatar should have been nowhere near this squad. It should have been largely fringe players and some new ones to try out, and anyone who’s returning from injury if there is anyone. If it didn’t work it doesn’t matter as this is a pony tournament anyway.
Southgate never had players for that long together in one go, apart from in tournaments, due to Covid it was perfect chance to look at players like Maddison, Justin and more. He could have unearthed a gem or two to give a look at in the next two games with a full squad.
There was far more to gain from doing that than from what actuallly happened in my opinion.