Is there a way to place an adjustment clip on a track with two clips side by side on the edit page and set a transition with the adjustment clip?
Am I correct in understanding that it is assumed that there will be a smooth transition between two consecutive clips on one track?
In that case, you can't do it with the adjustment clip.
Adjustment clips are processed on the composite video below the track where the adjustment clip is placed.
Transition is a method that uses the blank space before and after two consecutive clips on one track. (There are also options such as front only and back only.)
Adjustment clips process the composite video of the underlying track, and do not recognize margins, so processing such as transitions is not possible.
If you want to gradually turn off the display and then gradually display it when moving to the next clip, this is also possible with adjustment clips. In that case, open the adjustment clip in Fusion and process it using keyframes.