you can use the rollback (I think that’s what it’s called) from the history setting.
open The history settings from the setting tab/menu
select the History period you want to see ( when did you delete the module/formula)
look into the history entries until you see the delete action you would like to reverse
select the history entry right before the accidental delete
select “restore to ID” button at the bottom right.
confirm and the system will restore the state of the model to where it was before the delete.
when you perform the rollback, EVERYTHING that has been added or updated since the point you selected will be deleted. That includes changes to other modules and changes made by other users. So you have to weigh this action carefully.
Einas "Give a Man a Fish, and You Feed Him for a Day. Teach a Man To Fish, and You Feed Him for a Lifetime"