Imported item to sketchup is 20m edges 11m faces - SKP file is 8mb

We have a small SKP file users are struggling with.
8MB total - model info : 23million edges, 11 million faces.

When I remove items one by one I see an object that when removed, reduces the count by 19.5 million edges.
How can this user ;combine’ the edges/faces of an imported ‘picture/item’ to lower the count and speed up the model?

thanks in advance.

Just remove the bloat and forget about it. There are polygon reducing extensions like Skimp but removing 95% won’t produce an usable result.