If you are willing to pay for custom covers, a good shop can modify the foam's shape, thickness and material density on your stock seats to give you more lateral support and greater comfort. That won't offer all the newer adjustments but it will dramatically change the comfort and feel.
OPGI carries these Procar buckets starting at $530 a pair. Add headrests $590 a pair. https://www.opgi.com/skylark/CH22474/
Would love to find something with lumbar support , bad lower back. Did any of the Riviera's ever come with plush buckets ?