Without having the 3mf to test, this is all guesswork.
Your model looks very detailed (from the limited area that can be seen), plus the 1m warning.
There is no ability to determine the model width and depth based on the zoomed-in views.
You appear to be trying to print all this detail over just 50 layers, just over 8cm.
This will remove lots of detail.
Is this your design or someone else’s?
Have you resized it?
What are the dimensions of the original width, depth and height (and after the resize)?
It looks like a model of the New York coast and Central Park. This is a significant amount of detail in a small footprint.
Is there a link to this model (assuming it is from someone else)?
I bought it on GTrader. Original size is 77mm height average ~4mm. Very small for all that data. I scaled it up by 4 when creating the 3MF. And in preview mode the increased size object still looks perfect.
As I suspected, far too much data in this model to be printed in a single piece.
Based on the listing, this is not a 3D printable model, it is just a 3D model.
It contains GPS data, which makes it far more likely that this is designed to be more suitable for use in video games, for architects, and by those who require this amount of highly detailed data.
The only way to print this and have it look decent is to split it into many smaller cubes before printing individually, and then join them together.
You would end up with a large model in the range of many feet.