It's worthy learning outdated frameworks?
One of the JAMStack tools I've spent more time playing and building was Gatsby but since the Netlify's adquisition it has lost status and updates.
Once one of the best tools to build websites now it's a ghost. And most of the community it's recommending to move to Astro or Remix, althought the project it's not official dead but with not more updates or innovation in the last three years it seems that the final is inevitable.
There is one question that it keeps showing in the forums and it's "It is worthy to learn Gatbsy?" I think it is.
Mostly for two reasons: to learn a simple tool and to learn how to migrate from Gatsby to another meta-frameworks
And this applies to another old technologies. You could learn them and apply to jobs that are migrating from an old version to a new one or another kind.