@pagat long games are typically very hard for me to get through, especially these days. That's mainly what kept me from baldur's Gate 3.
One of my favorite RPGs, Ara Fell, is something like 20 hours. My game's main story is about 6, and with all the extra stuff to do in the world I think it would probably take somewhere around 15 or 20 if you did everything. I'll find the exact time soon enough lol.