The thing I dislike about modern Lego is that the sets are based around building the thing that is pictured on the box.
So what then? You’ve built it, do you dismantle it and build it again? Do you put it on a shelf and look at it? Do you play with it?
When I was a kid we dreamt up things to build, we used our imagination, not follow a set of Ikea-esque instructions.
A lot of the (bigger) kits have at least two ways you can build them, and once built and played with all my kids lego goes into the big box, and there’s nothing to stop them building something else with it.
(And the old kits also had Ikea-esque instructions, I can clearly remember following them over 30 years ago…)
OP: A play tent would be good for a 4 year old.