A solution to black out part of a clip?

I have a 3 second PNG on video track 1. After that, a screen recording from Windows. I put a cross dissolve on the middle, between the clips. It works as expected.

Because the video is a recording of my screen, I don't want the viewer to see my Windows task bar. So I made a transparent PNG, except the bottom is black. I put that new PNG on video track 2. It only stretches out over the length of the video, as I don't want it on the PNG on track 1. Now, it works as expected.

Except, at the cross dissolve, where the last few frames of the dissolve shows the bottom of my taskbar. I assume, that Resolve takes the first frame of the video, to do the cross dissolve, as the effect starts on the PNG. The dissolve is a second long, so I could stretch the PNG on track 2 to be half a second into the PNG on track 1, but then it looks odd.

I need a better solution, and preferable one I can just drag onto each clip, as I have many dozens of clips on my timeline. I assume I need to either use an adjustment clip, or a Fusion composition. I know, Fusion compositions can somehow be exported as an effect, but I don't know if these effects can be dragged on to the video clip. If they can only be dragged on a new track above, it really doesn't help me.

You could try using the crop controls in the inspector for the screen recording if all you need is to remove the top and/or bottom of the clip. In fact, this can be applied to one or more selected clips in the bin before dragging them onto a timeline. Would that work for your use case?

Well, that could work for my next project, but not for this one. The project is almost done. I only discovered the error, because I made a draft output video, and watched it through. The video is 40 minutes long, with many dozens of video clips (cuts) and screenshots of a Windows screen.

I could of course re-encode the 20 or so video clips, the video is made out of, and in the process cut out the botttom x pixels or simply put a black bar in the bottom. Unfortunately, even when closing and re-opening Resolve, changes in clips, audio and screenshots, are not being updated.

You could also select all the screen recording clips on the timeline and then modify their cropping (all at once). If you decide to try this, make a copy of your timeline before you do so that you have a fallback if something goes wrong.

Or you can put the original leading clip on a separate track and use fade handles to fade out the leading clip over a fade-in of the screen clip (the old fashioned way of performing a transition).