Editing non-uniformly scaled blocks

A couple of objects in my project are causing issues - too much complexity for the number of detail viewports on my layout, I think.

I am seeking to reduce complexity by removing .jpgs applied to the objects.

My strategy is to insert the non-uniformly scaled blocks into the project from the block manager and edit and save them as desired (colour ByLayer, I think), so far that hasn’t worked with the colour settings for the layers or groups in which they are nested, but I hope I’m on the right track.

Thoughts welcome.