Questions about modelling

I want to create a complex spaceship model with Probuilder.
But I am not so experienced and I don’t know how to do it the best way…

The spaceship is symmetrical and I would like to create only one side of it so I could modify it easily, adjust the UV only on this side and thus reduce the size of the prefab file. I basically want this to be optimized as much as it’s possible.

I don’t know if there is a way to do this in the editor, but if there isn’t I would like to know if it is possible and easier to make only one side of the spaceship and then duplicate, mirror and merge it together at runtime. Is this going to cause some errors?

Also, another question about editing UVs with probuilder. It’s really hard to unwrap the UV of a mesh. For example, when you open UV Editor for a bezier shape, all of the faces are scattered and when you have some cable texture which you want to tile along the bezier shape, you have to spend 3 hours resizing each face to fit the 32x32 texture you have, then you have to repeat the same process for all 10 or more cables you have, or replace each one of them with a copy of the one with the adjusted UV…

Probuilder and especially the UV Editor is so basic for me. Is there some better alternative for creating serious models?
ProBuilder doesn’t even have an option to cut a mesh, or mirror an object (or objects) using a plane, it is so basic…

If there is somebody more experienced at creating high-quality complex models please help!

Thanks for reading.

Blender is also a useful tool, and it’s free