As you already understand, it's time to get rid of the Tucson. The only question is whether it's more economical to replace the cat and quickly sell or simply trade-it-in "as is." It doesn't take an experienced mechanic (and, I'm not a mechanic) to tell you that it's time to cut your losses. Something caused the cat to fail and while it could relate to the CC, itself (or an attempted theft, etc.), there's obviously high probability of another, far more costly, cause. If you think your Tucson is worthless with an exhaust issue, wait until you throw a rod and blow the engine. Not worth the risk. Attempt to get accurate estimates for the value of each a working and dead 2018 Tucson. Once in hand, dump the vehicle, ASAP.
Unless you're savvy with cars and/or know a qualified mechanic willing to work with you on the cheap, a dealership trade-in is likely inevitable. In the old days, you could deal with mechanical problems by going to a salvage yard and buying used parts if you could install them yourself or knew a mechanic who would work with you to do the work. Here, even if you were an ace mechanic, I doubt that you could find a CC at a salvage yard. As suggested by others, I don't believe that they're even available for sale. In the absence of such cost-cutting measures, you're at the mercy of a garage, if you can even find an old school, independent repair shop. If not, you're limited to unreliable franchises like Midas, Mavis, etc. or unaffordable dealerships.
If it were my Tucson and the vehicle was drivable, I'd simply take it to a dealership, say nothing and see what's offered for trade-in. If you're ridiculously lucky, they might not fully appreciate the problem. But, assuming the problem is obvious, the value of the vehicle will be central to your negotiations. Unless you're a truly skilled negotiator, you should first negotiate the financing or lease for your new vehicle before swallowing the bitter pill of the low value of your trade-in, otherwise expect an amazingly generous offer for your shitty trade in exchange for paying top-dollar for the new vehicle.
For what it's worth, if the Tucson is in such bad shape that it's not even drivable, I would first call dealerships to explain the situation and attempt to get a guarantee for a minimum offer, sight-unseen, before absorbing the cost of having the vehicle towed for their inspection. Don't add insult to injury by having a wrecker take your vehicle to a dealership only to be told that they're not interested in a trade or are only willing to cough-up $500, etc. Remember, you've been dealt a bad hand, here. You shouldn't anticipate any favors.
Sorry for your situation. My advice, quickly address it and move-on. Regrettably, I've spent a good deal of time in my life dealing with these sort of concerns--even when I truly couldn't afford the consequences; even when I assumed that I was past such concerns; even when they only became my responsibility to help others. The faster you take care of the problem, the better you'll feel. In the end, it's only a car. There are far more worthwhile things worthy of your time and attention. Good luck.
Thanks!
Some good advice in this thread…sounds like general consensus is to sell the car and move on.
It’s been sitting at the Dealership for over a month as I’ve been trying to get them to work with Corporate to cover the repair, but that was denied.
I won’t ever be buying a Hyundai again so I’ll see what they’ll offer for a straight up trade in since it’s sitting in their lot. Unfortunately a CarMax type of place is going to want to inspect it since it has such as major issue and is pretty much not able to be driven at high speeds right now.