You are alone. There is a reason why the game turns into crap the moment Jackie dies. Why did we all love Jackie even though we spent so little time with him?
Because its what he represents, a big brother, a friend, a compadre, someone to lean on, someone to experience the world with, a loyal friend, he is Batou! Once he is gone you are alone and you have nobody to confide in or to experience the world with. This goes against standard RPGs where companions are everything. Yes keanu reeves comes into the picture with his douchy one-liners and emo attitude but I rather he didn't show up at all. He does not fill Jackies function at all. And so you become the loneliest protagonist in any RPG ever.
In CP2 I hope we can have several companions that follow you around and that you can bond with.
I agree that this is the main problem of the game.
You know a lot of people, but you're always alone.
Just like in FF XV, when they showed that Noctis and Luna were a couple, but never get to live with each other - only by "dog mail", despite her loss was really heavy for the character and with a very impactful animation, in reality the player never got to know her - so it was a shallow loss. Same goes to Noctis father.
But in FF VII, Aerith loss was much more meaningful, for the player specially, giving that "We can't let this Sephiroth guy get away with that" feeling. That's because she was very well developed as a character for storytelling AND for gaming purposes: she was always in the party, the player interacted with her, had very good stats as a healer - so she was useful, had some story with her in some parts of the game.
So, considering what was done in Cyberpunk 2077, V and Jackie become friends are resumed by the Youtube Promo video, instead of being properly developed in game missions, and all other friends/romantic options have some meaningful moments of talking, but you never get to do things wih them.
You can't call them to eat, drink and dance. Can't call them to help with some jobs and so on (except for Judy on one of her own missions).
When Jackie goes, it's a sad moment, very well planned, but a missed oportunity to make it carry more dramatic weight, to be more meaningful. Same goes to T-Bug, which you never really get to know, so when she passes it's like "ok, these things happen, people die".
And I only felt the weight of Jackies death when I visit Mama Welles and how she behaved, not because I bounded with Jackie (because the friendship was a promo youtube video, not actually game missions). To be honest, the weight of his loss is thanks to the spectacular job made by the voice actors (male and female).
So, the same goes for other meaningful friends/romance in Cyberpunk 2077. They're nice, but because you don't really do anything with them, no activities, no jobs and they forget you as soon as their plot missions are done, there is this feeling of emptiness, that something is missing. This is a big letdown in this department.