Hi finnaeus,
The Deluxe Faux Leather Platform Bed that swrstock linked would probably be a reasonable choice if the slats aren’t too thin or “bendy”.
Unfortunately the listings on Amazon and the many other online venues change too frequently for any single person to keep up with them or keep a list up to date in a constantly changing market so other than the suggestions in the foundation post I linked I can only provide the guidelines I would suggest looking for to help you narrow down your options and with “how” to choose and assess whether a support system would be suitable for your mattress.
Some of the wire grid platform foundations that have a stronger design and smaller “gaps” in between the wires could be suitable suitable choices (see post #10 here for more about wire grid platform/foundations) and some of the KD foundations that use 1x3 slats that aren’t more than 5" apart (closer to 3" would be better yet) would also be a suitable choice although they will also need a bedframe to use under them which would add to the cost.
If you are only considering Amazon then a search on terms like KD mattress foundation or on mattress platform bedframe will bring up many of the options they have available.
Phoenix