I would like to speed up the animation viewport. they are too slow it's very irritating I did low simplify. nothing works What can I do to fix the slow performance?
please also add picture As an example.
The Line Art Modifier is quite resource-intensive. You could disable it for the viewport only:
Enable it in the viewport only when you need to tweak its values.
Disabling it increases my uncapped viewport frame rate from around ~35 to about ~250 fps.
You should also set your timeline's Playback Sync to Frame Dropping or Sync to Audio if you have an audio track to animate to. The default Play Every Frame is suited only for physics simulations.