How to add a second field to the searchmodel for sorting without displaying on the UI?

Question

Yii

Case:
I import goods, when importing, everything starts with one date with a timestamp (I write it to creatred_at)
The searcmodel is 'defaultOrder' => ['created_at' => SORT_DESC] .
As a result, the field is sorted, everything works out, but after the changes, the date of the change is put in updated_at, and our line randomly jumps into the middle.
If I initially do 'defaultOrder' => ['created_at' => SORT_DESC, 'updated_at' => SORT_DESC], then it stops jumping, the necessary lines are where they should be, but in the view, sorting by 2 columns is displayed in gridview, and if I change sorting by another field, it is impossible to sort by 2 columns again. Can I somehow implicitly add sorting by the second column?