You are very limited, and depending on your exact situation you may even be more limited. Jenn Aire still makes them, but you will most likely only see them on the Jenn Aire web page.
I think, Dacor makes a compatible downdraft vent and downdraft range, probably pricey.
If you are trying to replace a broken downdraft range on a budget, it may actually be less expensive to install a different 30"slide in and an over the range hood. Is that at all possible?
You will need to be creative.

Thanks Local. I would lose a cabinet if I installed a range hood and my cabinet space is already limited. And my funds are somewhat limited as in ...I can't spend an arm
and a leg but I'll keep checking.

I have a Thermador that is almost 20 years old now and am replacing it with an induction cooktop and double ovens. I am done with the range with downdraft. They don't make any to choose from anymore. I searched for a long time to find one to replace what I have which is probably a lot like what you have. One thing that always bothered me about this range is that the depth of the interior of the oven suffered. Even though the range sticks out 3" more than I ever thought, it still is not a full depth oven. I was surprised that Thermador quit making their downdraft range and good luck to you finding a downdraft range to replace your JenAir. The companies that seemed to make them quit making them soon after. Searching the net and calling companies took up much of my time for a while until I gave up. At least my downdraft is actually an updraft so I can put in a hood and have it exhaust out the top to the roof. You might end up having to do a updraft and just a range. Dacor had a unit but upon looking into it further it was no longer available.

The Jenn Air website shows 2 duel fuel slid-in ranges with down draft and 3 electric slide in ranges with down draft. The website has a showroom search tab so you could check for one near you. Since they have those ranges on their website I would think that they could be ordered through any appliance store that carries Jenn Air.

I've recently replaced an old Amana electric downdraft range with a Jenn Air downdraft range. So far, I like it. It has a convection oven and a smooth glass top,which is easy to clean. It was reasonably priced. I was hoping to find a downdraft range with induction but there is no such animal. Maybe next time we update. Good luck with your search.