So yeah, 100% agree that the "big bulletin approach" is a negative.
I take screenshots of the state of figma at the time we all agreed that "this is it" (or close enough to what we'll implement). Sure I'll leave a link in the epic to the figma "bulletin board" for that feature so that people can find it and look around. But that's it. We're also never gonna implement exactly what's shown in figma (or said screenshots) either because it would take forever to get the designers to actually adjust everything to look like it does in product.
They can never seem to get the look to match what our standard UI library looks like. Which is a shame because every new developer always tries to match what the design shows instead of sticking with the standard library. Honestly, the best thing would be if figma wasn't used at all and the designers just used black and white lines and boxes and focus on good UX instead of pixel perfect UI designs.
For instance, if something is agreed upon and a designer changes it afterwards, they could simply give you a heads up that they intend to do so with context so the two of you can discuss.
People > process.
The flogging still happens. Is that broken? Yes! Does it still happen in too many companies? Yes! Is there an easy fix where you "trust but verify"? Yes! (as in, sure I trust they will notify me next time, which even if they actually do may be too late. So we made the process "figma is the 'working theory' and what we actually build will sorta look like that". Not every stakeholder may understand that but we sure will tell them when the flogging is about to start. (I say flogging, but in reality it's a gradient of course and while in some companies it will resemble an actual flogging quite closely in others it's more like what you describe. Not all countries and companies are as chill as some others ;))
That's why I really like working in true cross-functional teams. A Product Manager, a Product Designer and a handful of engineers. Do standups and all ceremonies together.
Ideally this "product team" is also empowered to solve a problem instead of tasked to build a feature.