Is it worth rebuilding my transmission or should I just sell

I've been going back and forth on this for weeks now and I honestly can't make up my mind, so I'm hoping some of you who've been in a similar situation can weigh in with your thoughts. I've got a 2013 Q5 that I absolutely love, but the transmission has been giving me trouble for a while now and it's finally reached a point where I can't ignore it anymore. The shifts are getting rougher by the day, there's a noticeable delay when I accelerate from a stop, and I can hear this faint whining noise that gets louder as I speed up. I took it to a mechanic for a diagnosis and he confirmed that the transmission is on its way out and needs a complete overhaul. The quote he gave me was significant, around 10,000 dirhams, and I'm really struggling with whether it makes sense to invest that kind of money into a car that's already 12 years old. On one hand, the car is in great condition otherwise. The body is clean, the interior is spotless, the engine runs beautifully, and I've maintained it really well over the years. I know the full history of the car and I trust it, which is something you can't say when you buy a used car from a stranger. On the other hand, I'm worried about throwing that much money at an old car and then having something else major go wrong a few months down the line. It's such a tough call because I love the car but I also don't want to be that person who sinks way more money into a vehicle than it's actually worth. I've been doing a lot of research online and I've seen some discussions about where to go for a genuine gearbox overhaul for Audi vehicles in Musaffah, which seems to be the area where a lot of the transmission specialists are located. I'm thinking that if I do decide to go ahead with the repair, I want to make sure I take it to someone who really knows what they're doing and uses quality parts, not just the cheapest option. But I'm also wondering if maybe I should just cut my losses and sell the car as-is, then use the money I would have spent on the repair as a down payment on something newer. The problem is, with a failing transmission, I'm not going to get much for the car in a private sale, and a dealership will probably lowball me even more. I feel like I'm in a no-win situation and every option seems to have its own set of risks and downsides. Has anyone here been through this kind of decision-making process? What did you end up doing and do you regret your choice? I'd really appreciate hearing from people who've been in my shoes because right now I'm just stuck in this cycle of indecision and it's driving me crazy. I need to make a decision soon because the car is getting worse and I don't want to end up stranded somewhere. Any advice or perspectives would be incredibly helpful right now. Thanks in advance for taking the time to read this and share your thoughts.