Hi bonepetit,
I’m sorry to hear that your initial experience on your mattress wasn’t particularly good and I hope that any softening during the break in and adjustment period is enough for you to sleep well on your mattress.
When you buy a new mattress you will generally sink into it either more or less than your old mattress so it’s not unusual to need a new pillow with a different profile as well. A suitable pillow is an essential part of good alignment for the head and neck and upper body because the gap between the head and the mattress and the curve of the cervical spine needs to be supported just like all other parts of the spine. Like mattresses … there are certain “needs” that depend on body type and sleeping positions but with pillows, personal preferences play a more important role because the face is much more sensitive to textures, temperature, smells, and other more subjective “feel” based properties of a pillow. There is more about choosing pillows in the pillow thread here.
If the only issue with a mattress is that it is too firm and there are no soft spots or sagging in the mattress then a good quality topper can certainly be an effective way to add some additional softness, “comfort” and pressure relief to your sleeping system but the only way to know for certain whether a specific mattress/topper combination is a good “match” for you in terms of comfort, firmness, and PPP is based on your own careful testing or personal experience on the combination. If you can’t test the combination in person then there will always be always some risk and uncertainty involved in adding a topper because the specifics of the mattress itself along with your own body type, sleeping position, and preferences can affect which specific topper would be a suitable choice on any specific mattress.
There is more information about choosing a topper and a link to the better online sources I’m aware of in post #2 here and the topper guidelines it links to which along with a conversation with a reliable and knowledgeable supplier (that can provide you with good information about how their toppers compare to each other or to other toppers they are familiar with that are available on the market) can help you use your sleeping experience as a reference point and guideline to help you choose the type, thickness, and firmness for a topper that has the least possible risk and the best chance for success. A good exchange/return policy can also reduce the risk of an online topper purchase so I would make sure you are comfortable with the options you have available after a purchase just in case the topper you choose doesn’t turn out as well as you hoped for.
If a mattress/topper combination turns out to be a good “match” for you in terms of “comfort”, firmness, and PPP then having a separate topper also has the advantage of being able to replace just the topper without replacing the entire mattress if it softens or breaks down before the upper foam layers in the mattress (which is very likely because the upper layers of a sleeping system tend to soften or break down before the deeper layers) or if your needs or preferences change over time. A suitable topper can also help extend the useful life of the mattress underneath it because it will absorb much of the compression forces that can soften or break down the top layers of the mattress underneath it over time.
Phoenix