Hello there,
How to import a 3d rendered Blender movie file with transparent background into ClipStudioPaint?

Let me explain a bit.

I created a 3d model skull in Zbrush than imported the file into Blender 2.90 and 2.93 made an animation of the skull that I created and wanted to import the final render animation video file into ClipStudio Paint EX because I wanted to create a stylized animation with drawing background for my 3d animation model. The plan is to create a trading card of it with an animation, so I can post the animation and then the card.

But every time I want to import the rendered animation file in ClipStudioPaint I got an error.
With the hint "File import failed".
Okay, I rendered the animation with an alpha, so it is a transparent animation. In Photoshop after encoding it to another codex it solved the problem with Photoshop but not with ClipStudioPaint. Every file I want to import, I got an error.

I used serval codex. Quicktime Animation, FFMPEG in Blender with Alpha.

The QuickTime Render with H264 with MP4 without alpha, with black background is working, but the others are not.

I try almost everything and only the full MP4 render with black background was successful, see last picture, but this has of course black background. I wanted to get rid of the background, because I wanted to draw a layer under it and create so a 2d/3d animation samples for my trading cards.

Off course, I can do this all in After Effects and Photoshop, there is everything working fine.
But I wanted to keep everything in ClipStudioPaint the animation and the trading card I am planing to do.

What did I wrong, and which render I can use to create an animation with transparent background that ClipStudioPaint can accept? Or is this not possible?

I used Blender because it's free, and I have no access to Maya or Cinema4D, but I have a friend that have Cinema4D.

Any help would be great. What Did I wrong, and what's the work around about importing transparent video files into ClipStudioPaint? Or is this not possible in ClipStudioPaint?

Thank You for any help and for reading.
Jakob Miernik