Genuine question for the group rather than advice from me, because I have opinions and no way to know if they are right for someone new.
My instinct is: do the opening, then ignore every marker for an hour and drive somewhere. But someone who has never played one of these might get more out of following the story until the systems make sense.
What did people who came to this series late actually wish they had done?
Accepted answer
My honest answer for someone new is the opposite of my instinct for myself. Follow the story until the systems have been introduced, then stop and wander.
The reason is that these games teach you their verbs through missions. Wandering first is wonderful if you already know what you can do and disorienting if you do not.
I came to this series from Red Dead and I wandered first and it was a mistake. I spent four hours not knowing there was a whole system I had not been shown.
Worth saying plainly for the group: the first two hours are the least replayable part of the game. You only get one first impression of that city.
For a newcomer I would add: do not open the map screen for the first hour. Let the city introduce itself before the interface does.
Do the opening, then go find one thing that is not on the map and look at it properly. That is the compromise version.
Saving this. Between this and the wanted level explainer I have a plan for a game I have never played.
do the opening then go somewhere you were not told about. that is the whole game in one instruction
This is the advice I was hoping someone would give, because I was planning to wander immediately and I would have had no idea what I was looking at.
The first two hours being the least replayable part of the game is the kind of thing that is obvious and that nobody says.