Soft Picture Quality even with video passthrough enabled

So I have been running some picture quality tests on my Bolt and I've found that the picture quality is significantly softer on both my 2016 Vizio P-series TV, and my LG B6 Oled via the TiVos, than it is if I copy the recording directly off of the TiVo and play it back through my Nvidia Shield TV via Plex or Kodi.

I have tried using both video passthrough, i.e. enabling all of the separate output resolutions on the TiVo (720p, 1080i, etc.), and allowing the TV to perform the scaling, as...

Soft Picture Quality even with video passthrough enabled

Soft Picture Quality even with video passthrough enabled