[SalesForce] Custom Settings – Validation Rule

You can assign a fault connector and screen to any lookup or DML action. This should capture a validation rule...although I'm not sure if it will on update of a child causing a validation rule on the parent.

All you need to do is create a screen with a text output that uses the merge field {!$Flow.FaultMessage}:

Then connect the action element to the screen - to do this your element needs to be connected to something else first, the second connection will be for the fault. If it is your last element drag to the fault screen twice then select the connection and press delete. You should be left with the fault line. Below is from a record create, but it could be a record update, lookup or delete:

A problem with switching to the name is that in triggers only the immediate fields of objects are available. So RecordTypeId is available but the related field that has the record type name RecordType.Name is not without performing an extra query.

ID values in sandboxes are the same as in production because a sandbox is a clone of production.

So I suggest that you do not make this change.