Pattern images don’t allow image replacement, only transform

I’m running into a beginners structural issues using patterns with GenerateBlocks media image blocks (block patterns and starter site patterns)

The patterns contain designed image blocks that:
• appear as Image blocks in List View
• use a GenerateBlocks media ID (e.g. gb-media-xxxxx) on the block editor
• BUT do not allow images to be replaced directly – the only option being to “Transform to Image”. If I choose transform, this then breaks the layout, sizing and pattern completely.

Is there a way to simply swap images into image blocks in patterns while preserving the pattern structure?

Thanks.