Unable to lock the screen with double tap gesture

Nova launcher has always been my default launcher & I recently upgraded my phone to one ui 6. Since then I'm unable to lock my device with double tap gesture on home screen. (context)

After going to accessibility settings, the nova launcher is greyed out as it is shown in the image 2. After clicking on the greyed out area it shows message which is given in image 3.

I selected option 1 (accessibility) in image 1 as selecting option 2 (device admin) is not allowing me to unlock phone via fingerprint after locking.

I tried finding that option but couldn't locate. Any idea how to resolve it?