Someone said in comments before that stocks/crypto dont count since they fluctuate quite heavily. Do you have an LLC where you send yourself some form of "salary" for expenses? You can create a contract for yourself with that LLC, explicitly stating you can work remotely from Thailand, with that company.
More than enough. Did you apply in Hanoi? I just submitted the stamp and my Airbnb booking and I was not asked for further proof of being in the country (I still am, waiting for my visa to be approved)