The source RAW quality is so ridiculously awful that even if you reencode it using x265 with a bare minimum quality rate factor, you'll end up with a larger file than the source. This is because the artifacts are all seen by the encoder as more details it needs to encode, not to mention all of that blur. The more artifacts and the blurrier the image, the worse the compression efficiency when you try to reencode it.

Since you release on Wednesdays, I would very strongly recommend you find someone who can hook you up with an AMZN raw instead of TTFC. TTFC has gone to complete shit, and their raws shouldn't be used anymore by anyone. The only downside to AMZN is that they release late, on Wednesdays... but since that's when you release there should be no problems there.