Many designers want to leave Adobe but can't due to missing plugins and integrations. An opportunity exists to build compatible extensions for new open tools.
Develop popular Photoshop/Illustrator plugins in Rust/WASM for ArtCraft and similar suites. Focus on most-missed features like content-aware fill.
Sell through marketplace with revenue share to host platform. Offer some free plugins to drive adoption.
Start by porting one essential plugin with good documentation.
Risk is platform API instability during early development.