I have built a white concrete wall and I’m trying to make it so a design made of blue concrete is revealed with a command block.

I’ve tried a few different ways, but so far it hasn’t worked:

• give the blocks a custom tag and use a command to only fill the tagged blocks with blue ones (I haven’t found the right syntax for this)
• change the color of my blue blocks so they all look white and then restore their color (I saw a post about it but very few examples)
• use /setblock for each block of my design, but it seems I can only do one block at a time and I feel there must be a better way

Finding information is difficult, especially because a lot of the code I find is either outdated or for bedrock.

But it seems like it should be possible, right?