PoE++ can get warm but you wont be doing that with fibre!

Before specifying fibre everywhere I suggest you note that a CAT 6 cable can manage 10G and PoE++. Its a lot more resilient to breakage too, especially outside the data centre.

If you really want to blow some cash there is CAT6A, which is probably not indicated unless you want cable lengths of more than say 50m.