It really depends. Some Genshin story quests are relatively short and can be done in an hour or two. But complex ones could take five or more hours to finish, depending on your gameplay speed and how much you explore the details.
The length of Genshin's story quests is quite variable. Simple ones might be done in an hour or so, but more elaborate and challenging ones could take three or more hours. It all depends on the depth and scope of the quest.
The number of story quests in Genshin Impact varies over time. As of now, there are dozens, but the developers keep introducing more to enhance the gaming experience.
The length of story quests in Genshin Impact is inconsistent. Some are short and straightforward, taking maybe an hour or so. Others are more complex and could take you three or more hours to finish, especially if you take your time to enjoy the scenery and lore.
Generally, no. Story quests in Genshin are designed to be completed in sequence and cannot be canceled mid-way. This is to maintain the integrity and flow of the game's narrative.