I haven't been following closely lately, but yes, its a cool idea. However, it have almost stalled for many years. Not because of the project, but the idea never caught on with distros etc.
They have kept watching/working on it though, and latest push I think, were a tech-demo distro where you login via the SOLID ecosystem and keep your data etc there. I forgot the name, but it should show up in distrowatch searching for 'solid' - I presume.
I think most sota llm's knows enough about Solid to help with small apps etc for it.