You don't need to leave every six months. You can stay one day and leave, then come again and stay one month, and leave two months. It's totally free and up to you. Each entry grants 180 days.
they might not even understand the numbers or words 🤷🏻, not to mention grasping the exchange rate to translate it to Thai baht or USD. In my case, my bank is Korean and so the app and everything is in Korean language (and the money is in Korean won, of course). Some countries write one million like 1.000.000 while others write it 1,000,000. Some others, reportedly, separate the numbers every four, not every three (India, I heard). In Korea, China and Japan, in some cases they use "man" so 1 million become 100 man (100만), although that's mostly used in company statements not bank accounts, but see the point.
they might be jealous, not of the visa itself, but of other fellow foreigners being able to come here with "less efforts" than them. I mean, I wouldn't, but that's a possibility.
For workcation you'll need either documents of your own company or documents proving you work for any other individual or company. Just saying you work remotely but not for whom, won't work.