Is it possible to set a custom max animation framerate?

Is it possible to set an animation to run at maximum 10fps, to achieve a “retro effect” if you like?

So, overall game runs at 90-120 fps, but animations look like clay animations without the interpolation.

OK so the frame rate is the frame rate and by just changing the rate does not create the illusion of clay animation. Your solution is not just changing the rate but by changing the animation curve that the interpolation is using as the time line moves through the sequence.

The effect of clay animation is based on a step curve where the key pose frame is held until the following step key frame that changes to the next pose in the sequence.

This is a goodish example of using step curves instead of linear or Bezier