I suspect the chances for "brain rot" increase the farther one lives from a major Thai city. Having visited the countryside many times, there is simply no way I could live there. To each his own. Maybe when I'm an old man and watching grass grow becomes riveting, I could do it, but not until. In Bangkok, especially owning a company, there's plenty to keep one stimulated. The area where I live, despite being smack in the middle of this 11+ million person metropolis, is like a small neighborhood, everybody knowing everyone else and catching up on chit chat as time allows. We celebrate each other's birthdays, among other things. In my gym, with its mix of foreigners and Thais, meeting people is easy, as when faces become familiar, conversation naturally evolves. My best foreign friends were met in the gym, and I've dated Thai women with whom conversation emerged from familiarity. Bangkok Thai women also seem to have a lot more worldliness than rural women, which is understandable. That not only helps with communication (my Thai is not great), but the women have international travel experience and lots of knowledge about things not Thai. Thus, I don't think Thailand---particularly Bangkok---necessarily leads to brain rot. Life here can be as vibrant and stimulating as anywhere. Up to you.