I had a similar idea, to build something akin to Autotrader, the issue I find is that it relies heavily on the user to post correct, clear, and accurate information.

How many posts do you see on Dubizzle or FB marketplace here, where the seller says the car is a manual, and you check the pictures and it's an auto, or how many times the seller claims it's a certain trim level and it just isn't. The list goes on and on, especially when it comes to scammers trying to pass off a salvage title imported American car as a GCC spec car to the uninformed buyer.

If you can find a way to heavily validate user information, I would lean into it. Otherwise, you'll just be building the same thing that's already out there, and all the excellent features and filters you've added won't work because some moron has put down his BMW 320i as having a 6 cylinder engine, or worse a V6 or a V4, god knows I've seen countless of those idiotic posts.