. You can also have a combination of funds in the bank plus monthly income. As long as it equals the 800,000 baht. Example, you have 400k and show 33k monthly income is accepted. Although rules change all the time so yes, best to check with immigrations.
I have a us and canadian passport. I often use one to get in and another when leaving. I use my Canadian passport to travel worldwide depending where I’m headed. Some border agents see both my passports though.