You do not necessarily need an orthopaedic pillow from a specialist supplier (with a specialist price attached); broadly speaking, you just need something that maintains your body in good head, neck and back alignment. Because of this, the sleeping position you favour is important to your requirement:

if you sleep on your side, you will need a higher pillow than if you sleep on your back, and if you sleep on your front, you probably don’t need one at all.

If you sleep on your side, try to use something that supports your neck as well as your head (this is a feature of orthopaedic pillows, but you can achieve the same result with a bit of effort by tucking the pillow under your neck). If you are struggling to find a comfortable sleeping position for your neck, it may be worth seeing an osteopath in order to assess your vertebral alignment and posture.

Finally, the softness of the pillow is a matter of personal preference so long as the support is adequate.