My Q50's transmission is acting weird, any Infiniti specialists around?

I've owned my 2017 Infiniti Q50 for about three years now and it's been such a joy to drive, honestly one of the best cars I've ever had. But recently I've started noticing some really odd behavior from the transmission, especially when I'm in stop and go traffic around the city. It feels like it's hesitating or jerking when it shifts between first and second gear, and sometimes I get this rough thud that makes me cringe every time. I took it to a general garage in Mussafah and they did a transmission fluid flush but it didn't really solve the problem, which makes me think it might be something more complicated like the valve body or even the torque converter. I'm really worried because I know Infiniti parts aren't cheap and I don't want to end up at the dealership where they'll charge me an arm and a leg just for diagnostics. I heard about Master Infiniti Repair in 800Sayara Abu Dhabi and I'm wondering if anyone here has experience with them, especially for transmission issues on the Q50 or Q70 models. I need someone who really knows these cars inside out, not just a general mechanic who's guessing. Also, has anyone else experienced this kind of rough shifting on their Infiniti and found a fix? I'm hoping it's not something catastrophic because I genuinely love this car and I'm not ready to let it go yet. Any advice would be really appreciated, I'm kind of stressed about this whole situation to be honest.