Becoming tax resident does not mean you have a tax liability in Thailand. If you bring untaxed earnings onshore to a Thai bank account, you have a Thai job, or you have investments in Thailand then you have a tax liability here. If none of those apply just enjoy your holiday.
Once the visa is issued you never need to show the money again unless you want to stay more than 6 months and apply for an in country extension. Your visa will be valid for 5 years from date of issue with unlimited entries of 180-days
The 180-day tax residency has always been a thing but only the last
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years has everybody been panicking about it. Being tax resident does not mean you have a tax liability. Only if you bring untaxed money onshore, earn money in Thailand or have investments in Thailand do you require a TIN and file a tax return, otherwise just enjoy your holiday in Thailand. As a tourist you are not even allowed a bank account so stop worrying about tax liability.