"Now the ones I buy for my nephew give you a handful of bricks to make a specific thing."
Buy different kits then. There's still plenty of kits which have little-to-no custom pieces.
Here's the first kit that come up for me on Amazon, and I can only spot a few "non-brick" pieces. There's the moped which looks like a modern version of x81c01 from thirty years ago, the parasol, and the weird chip/fries thing. All the other pieces are the sort of bricks Lego have always been making.
Just be a bit more selective when you're looking for Lego, rather than buying the first one on the shelf.