It's not straightforward to pinpoint exactly where Dr. Stone Season 3 ends in the manga. Different factors like pacing and story arcs can influence it. Usually, you can look for key plot points or consult fan discussions for a clearer idea.
At the moment, there's no definite information about more Dr Stone manga. It could happen if there's enough demand and the creative team is up for it. We'll just have to wait and see.
It's hard to say for sure. The decision often depends on various factors like the popularity and sales of the original series, as well as the author's plans and the publisher's strategy.