Are you trying to achieve this through blueprints? I’m not actually sure if it’s possible to clone objects within blueprints or not (I’m sure there will be a way), however I thought I might offer an alternative approach.
To me, it sounds like you want to basically capture the history of ‘brush’ strokes made by the player. Presumably to play back later or allow some undo / redo option. Capturing a render texture for each of these periods will become expensive. It can be quite slow and will use a lot of memory (which will be a problem if you’re releasing on a mobile platfom). So instead, why not record information about the brush as it paints. You can capture all of this data into an array each frame, or at some suitable time interval and then when you need to, you can ‘replay’ that stroke simply by running the array and performing those actions again.