Nissan Moco Strange Problem Help Please

Hey, so Ive got this Nissan Moco 2015 that we imported in 2017. Its been with us ever since, so were kinda like the first owners, you know? When we got it, it had already been driven around 7000 km, and now its at 127k.

Honestly, Im not really a car expert, and I only started taking care of it after my dad had his leg amputated last year. On December 1st, I changed the gear oil because sometimes it would jerk unexpectedly when the AC was on. A mechanic whos a friend of a friend recommended using CVT gear oil, which I got from Karachi. Usually, I would ask my friend for help, but unfortunately, he passed away. Oh, and we also changed the spark plugs back then, but we used Chinese ones.

About a month ago, the car suddenly turned off while I was in Eco IDLE mode, and it wouldnt start again. Thats when the check engine light came on, indicating an issue with the catalytic converter. So, we cleaned the converter, cleaned the fuel system, and added a catalytic converter cleaner to the car.

But heres the thing, a few days later, it started jerking. Its like these slow jerks that happen when I accelerate, and even when Im cruising at a constant speed of 60 o r 80, it feels like the car is struggling to move forward, like somethings holding it back.

Ive been to four different mechanics since then. They replaced the spark plugs just two days ago because the check engine light was flashing during those jerks, but the problem still persists. They also did some work on the transmission and fixed a vibrating issue when the car was in Drive o r Reverse. They checked the coils, fuel injector, fuel pump, and even the catalytic converter. Last night, they even changed the oxygen sensor. But heres the kicker: there are no diagnostic trouble codes DTCs, and the jerking hasnt gone away. Sometimes its more noticeable, sometimes its not.

Now, there are only two things left that the mechanics suggested. One said I should take the car on a long drive for about 100 km to see if it helps get rid of any air in the transmission. And another friend thinks it might be time to replace the whole assembly.

So, guys, can any of you help me figure out what could be causing this? Im really stressed out about it. My dad and I are the only ones whove driven this car, and its driving me crazy.