Compare one factor at a time. If the bed is appropriately sized and stable, try placing it near an established resting area while leaving other familiar options available. Watch whether the cat investigates or rests there during normal routines. If the cat chooses the same location but consistently lies beside the bed, texture, enclosure or temperature may be more relevant than position. If the cat avoids the whole area, consider noise, traffic or access around other pets. These observations suggest possibilities rather than proving a single cause. Avoid repeatedly changing the cushion, adding scents and moving the bed all at once, because that makes the result difficult to interpret. Keep the process calm and practical. A bed that remains unused may simply be the wrong style for that individual cat, and there is no need to force a preference to justify the purchase.
For example, move the same bed beside a chosen resting spot before changing its cushion. If you change both together and the cat starts using it, you will not know which adjustment helped.
For product comparisons alongside this advice, see Velvet Nest and Silver Velvet Nest. The details below explain their sizes and uses.
Further reading: cats.org.uk.
Velvet Nest
Silver Velvet Nest
AeroMat Chill Pad