Looking for an "all-purpose" avisynth script

[Bi11]

I used to use fft3dfilter(sigma=4, sigma2=0, sigma3=0, sigma4=0 bw=32, bh=32, ow=16, oh=16, bt=5) as an "all-purpose" filter at the end of every script to increase compressibility and actually increase SSIM with x264.

However, after using fft3dfilter for several sources and encoding with x264, when I actually played the videos I saw they were softer and less sharp than the original. Other denoisers like RemoveGrain, Undot, DegrainMedian, TTempSmooth, etc..., had a similar effect but they would also give rise to various artifacts, like reducing the brightness in small eyes.
I think the word for what was removed/missing is "complexity". The same complexity AQ and Psy-RD try to retain with x264.

So now I try to avoid denoising unless it's necessary. Instead, for real-life videos, I just load the video, do the necessary filtering to make the video look flicker-free but still complex (like deblocking with deblock_QED then slight kernel shapening with LSFMod to enhance detail), then encode with x264, generally using the following parameters:

x264.exe --preset slower --tune film --aq-mode 2 --psy-rd 1:0.25

So since you're testing, try encoding the video (using the above settings with 2-pass to ensure comparable bitrates) without any post-processing and compare it with the post-processed encodes.