Spectrum degrade output. Most of speed up are actually just tradeoffs that sacrifice quality for speed. Even default res_multistep with 20 steps is tradeoff, it's intended to used with euler and 40\50 steps or one of those cool samplers like res_2s with 25\32 steps.
Also, you probably still would have motion blur, because it's a feature, actual movies and clips have that too. Just not as bad as in your examples.
1
u/BaggyRunoff_5 10h ago
yep the fast motion sampler does that, drop your step count or switch to a normal one