To a large extent, it is. The show takes inspiration from actual cases and tries to present a realistic account. However, there might be some artistic liberties taken for dramatic effect.
Season 2 of Dr Death is indeed based on true incidents. The creators have done research to bring those real stories to the screen, while adding some dramatic elements for entertainment purposes.
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.
Chapter 48 of the Hanging Long Pendant was a novel on the Long Pendant Literature Network. This novel is a pure love, modern, urban theme, and has been completed. The story was about a sweet love story between a gentle forensic doctor and a violent band's lead singer. Please read the novel for details.
After Season 3 of Dr. Stone, it's best to begin with Chapter 95. It continues the story seamlessly and keeps you engaged with the ongoing plot developments.