Are there any 3d print files available for free?I have a 3d printer but I am NOT skilled enough to design files.

You could try thingiverse. They have a bunch of stuff.

On Thingiverse, for Armada, you will mainly find models extracted from EAW video game. In my opinion those models don't have good enough details to stand next to FFG official minis.

Once I will be done with all the obstacles I'm planning on making a lot of ship and made them available on thingiverse, it will just take time ...