we stayed in Samui and had our kids in an International kindergarten and they loved it. The only thing that made us not want to go back there was the crowd😓Samui is suitable for vacation, not to live, in my opinion
I last visited Chiangmai (summer of 2019). It was so polluted and dusty that it turned me off. Bangkok is, like you said too crowded, Samui was nice but too touristy, and now we are looking at Huahin.