Ninja 300 2022 model’s engine turns off suddenly

I purchased a Ninja 300 last year and had been in an accident. I sent it to the service center for repairs and received it last month. Ever since, I have been facing this issue where after riding the bike for about an hour, the engine suddenly turns off while shifting the gear down to slow it. If I hit the kill switch and turn the engine on, the bike starts and I could ride it for another 5 minutes just to face the same issue. Initially I thought the engine is just heating up and is not able to cool down due to the hot weather. But this issue started happening often and I took it to the service center again. When I got the bike back, they said the coolant level in the bike was dangerously low and they had topped it up. Then for another week or so, the bike was functioning well. But I have started to face the same issue again. Has anyone faced the same issue or does anyone have a solution to this? This has made me lose confidence in my bike..