You cannot currently set the default value for a single select field. However, you can create an automation that triggers when a record is created and sets the value.
Note that if you create a lot of records, this could use up a lot of automation runs. Also there is a slight delay where the value is blank before the automation finishes running.
There are also a few other workarounds.
If you create a new record in a grid view that is grouped by {Stages} by using the + bar for the group, the new record will created with the corresponding {Stage}.
If you create new records using a form view, you can create and bookmark a url that prefills the {Stages} with the value you want.
