Epic, saga, tale. These words can be used in place of 'long story' in many cases. For example, instead of saying 'Here is a long story', you could say 'Here is an epic' or 'Here is a saga'.
A long account or narrative can also be considered as synonyms for 'long story'. An account is more like a report or description of events, often in a sequential order. A narrative is a story that is told, which can be long and detailed, just like a 'long story'.
A long tale. For example, 'The Odyssey' by Homer is a long tale full of adventures.
A long tale. For example, when we talk about the legend of King Arthur, it is like a long tale filled with adventures, romances and heroic deeds.
Some synonyms could be 'a lengthy tale' or 'an extended narrative'.
There are several synonyms, like 'it's a complex matter' or 'it's a convoluted tale'.
It could be 'it's a protracted account'.
You can say 'He told an elaborate account of his adventures.'
Narrative. A narrative can be a fictional or non - fictional account of events, like a historical narrative that tells about past events in a sequential way. It often has a beginning, middle and end, just like a story. It can be used to convey a message, describe a situation or share an experience.
Tale. For example, 'The Little Red Riding Hood' is a well - known tale. It has the same meaning as story, often used to refer to a fictional narrative.
Within the story, inside the story, as told in the story.