Where can I find a motherboard? Also, how can I transfer data?

So my Xperia X was dropped in water a few months ago and I’ve been using a cheap phone since. It doesn’t have a very good camera, though, and I miss my Xperia. I’ve narrowed it down to a problem with the motherboard, where I think some display ICs don’t work.

Where can I find a motherboard for this device? Would it be possible to fix the existing problems? Finally, would a transfer of data be difficult?