If Stremio updates
Run the newest Flux installer again after normal Stremio desktop updates. The Mac updater reapplies Flux when the Stremio server file changes and when Flux launches.
If Flux cannot recognize the installed desktop version, restore Stremio and wait for a Flux compatibility update. Do not keep reinstalling if Stremio opens to a blank screen.
What to send support
Send your OS version, Stremio version, Flux version, screenshot, diagnose report from the ZIP, and flux-compatibility-report.txt if it exists. That is what lets compatibility issues become fast fixes.