Figma sued AI startup Motiff in 2024 for copyright infringement and won[0]. Motiff had to reimburse figma, and redesign their product.

[0] https://www.courtlistener.com/docket/69166901/figma-inc-v-mo...

Not relevant. Figma v. Motif was over allegations of stealing source code, apparently including known Figma bugs.

The design of the UI wouldn't be covered by copyright anyway; Figma would have had to file and be granted a patent, which has a much higher bar (IMO not high enough, but that's a different discussion).