How can I mirror this noise modifier so that I get a loop animation?
1 Answer
F-Curve modifier Cycles > Repeat Mirrored ...
... but - Instead of F-Curve's Noise modifier you can use Noise texture in Geometry Nodes to offset location. To loop noise use Empty (or any other object) to control texture location and ensure start end Empty location match.
Like now this Empty animation generates visible back & forth motion. For nicer endless loop effect let Empty follow Curve Circle.