It's interesting that Mozilla has chosen to use an image with so much red, which makes JPEG (at their settings) look relatively poor even at quality 100. You cannot optimise the limitations of 2x2 chroma subsampling.

I am also not convinced by Trellis yet. In my tests, it introduced a faint blur. In fairness though, I only tried 4:4:4 and not 4:2:0 as Mozilla apparently does. In the latter case, additional blur may not be noticeable.