Let's Ask Cute Questions.
"What is your super-villain power?"
"What hobby do you wish you had?"
"When you were a kid, what did you want to be when you grew up?"
"What has your first job? Now, what was a time where you failed at it?"
"What musical instrument did you play as a kid? Now, if you put us all together, what band are we obviously?"
Questions like the above are... cute. Notice they are all versions of telling a story, which gets the team to talk, and hopefully listen to each other, which is what we want. You also don't have to ask them at the beginning of a team's existence. If anything, injecting an energy like what y'all had at the beginning keeps a level of novelty going, and more importantly, echoes how building relationships takes recurring effort. Let me say that again.
Building relationships takes recurring effort.
Asking cute questions is not a large time commitment. So what would be more of an investment?
Let's Do Something Together.
Ever go out to eat as a team? Followed by ice cream? Then espresso? People remember that.
Ever go out for drinks as a team? People remember... varying amounts of that.
Ever 'Escape The Room' as a team? Or trying? People definitely remember that.