Is the input shaper lying?!

I’ve got a shaper report that suggests ZV @70hz (on the X) and an accel of up to 20K , but I get rather visible ringing at anything over 5K . I understand the report is just an estimation but 20k to 5k is quite steep.

Any clue? I tried all the other shapers but the result is the same

Using the input shaper causes a “smoothing” of the moves.
Up to 20K means that with this setting the positional error does not exceed the defined threshold.
It is by no means an indication what your printer is physically able to handle.

See Measuring Resonances - Klipper documentation

okay that makes sense. so max acceleration is the maximum acceleration with the indicated smoothing (0.04 in my case). Over that acceleration I’d start getting visible smoothing. Thanks!