I think it's less important than how many large maps. in DOS2 you have 3 arcs but more than 3 large maps so it doesn't really say anything about the game's length ("arc 2" is very long in dos2)

Larian's Biggest Oversight, what to do about it, and My personal review of BG3 EA
"74.85% of you stood with the Tieflings, and 25.15% of you sided with Minthara. Good outweighs evil, it seems."