You can start from the chapter where the anime ended. Usually, there are online forums or manga communities that can give you the exact chapter number.
It's worth reading. The character development is one of its strong points. You get to see the transformation of the protagonist from a weak hunter to a powerful force. Moreover, the relationships between the characters add depth to the story, whether it's the friendships or rivalries that are depicted.
The Solo Leveling anime sticks closely to the manga. But there are instances where the anime might condense or expand certain events to create a more engaging viewing experience. The key plot points and character developments remain largely unchanged, though.