My first run of that divinity 2 took ~75 hours.
I had a great time. There are many QoL fixes in the steam workshop depending on your preferences.
Act 1 can be particularly rough if you're learning the mechanics and/or trying to play with others.
I don't think the game expects you to do everything in one run but you're welcome to try!
After seeing the mouse with ports on the bottom. I'm convinced that there's a disgruntled designer on their team and this is a cry for help.