I mean, there are some pillows that are firmer, like those filled with spelt or millet. You can also adjust the height by adding or removing filling. Downside is that they are quite firm, so not as soft to lay on.
There's also pillows filled with foam or plastic fibers, which spring back into form quite reliably, but they're horrid at transporting off the warmth and moisture from your head, resulting in you sweating a lot, so personally I wouldn't recommend them.
I remember as a kid, pillows would eventually flatten out into somewhat firm, thin bricks. These days, every pillow I buy breaks up into like 5 or 6 discrete clumps inside the pillow shell, none of which will actually flatten.
Two firm, flattened pillows are the perfect height. Two bag of big clumps are just as tall as two unclumped pillows, but neither provides any support.
None is great for lying on the back, whereas one is good for lying on the side, which I switch between regularly.
I've also tried pillows, which are only thick on the left and right, but in practice, I'll still have my head in the middle when lying on the side...