Hi Fran,
Only your own testing or sleeping experience can answer that (See mattress firmness/comfort levels in post #2 here about making comfort and design choices). It’s softer than many other support layers but for some people it would be fine and for others it may be too soft to provide good alignment. How evenly you sink into a mattress depends on your body type and sleeping positions and how all the layers of a mattress interact. The best way to know would be by testing a mattress that used similar layers but when you are making an online purchase that you can’t test ahead of time you are dependent on the knowledge and experience of the manufacturer in matching their customers to a mattress, on the options they have available with the firmness and softness of their comfort and support layers, and on any recourse you have available if your mattress choice is less than ideal.
Phoenix