I'm still not able to promise any exact timeline, but just to keep you all in the loop, here's the state of the project.
You might have seen some activity on the GitHub repositories. Some new progress has been made recently. A number of bugs have been fixed and many new extension hooks have been added, but it's still very incomplete. We are now targeting a January release for my client's app. Which means a first public release of Flamarkt should be able to follow shortly after.
That first Flamarkt version will still be very bare, because only features and extenders needed for my client will be implemented. There's also some code that's currently private that might be extracted to open-source extensions later on. The first new open-source extensions for Flamarkt probably won't come before March.
The decision was made to make Flamarkt PHP 8.1+, because that's what we are going to run in production with my client and the only version that will be tested. This joins the NodeJS/Puppeteer, headless Chrome and asynchronous queue requirements that were already decided earlier. The Scout extension is not a hard requirement but Flamarkt will be more difficult to use without it. MySQL <8.0 and subfolder installs will also not be tested. A future major version of Flamarkt, probably at least the year after might try lowering the most constraining requirements where possible.