Yes, there are two ways to blur the background when recording or editing a video in Detail iOS or iPadOS.
Option 1: Add a Detail Filter to a recording
Complete a recording of yourself or import a video of yourself or a person talking to camera
In the left-side menu, tap Filters
Tap on a filter, and tap again to open that Filter's extended menu – swipe up to reveal more options
Choose the background option (last 👤 icon)
Under Effects, slide the Depth slider to blur the background
Option 2: Turn on Portrait in your iPhone control centre before recording with Detail
Open a new project to record a video
Swipe from the top right corner to bottom left corner to reveal the control centre
At the top see Detail Controls, tap this to open the camera and microphone options
Tap "Portrait" to turn this option on when recording in Detail. This will lightly add depth to your video.