@Pete ******
Maybe you should just try to define what are savings in combination with remitted money.
From the view of Thailand savings would mean money you already paid tax for in Thailand.
From the view of the tax office of your home country it might be money you already paid tax for in your home country, and in some countries that means you don't have to pay tax on it anymore.
Unfortunately in Netherlands I have to pay tax also on savings...
So your statement that the fact savings are not taxed is basics, just is not true for all countries.
What exactly happens with savings when brought in from outside Thailand, depends on the DTA of your country with Thailand.
But in case there are no rules about this in the DTA, for Thailand any money brought in from outside is just taxable when it was not already in your possesision on 1-1-2024
Money you bring in to Thailand are not savings anymore on that moment, and for Thailand it were never savings.
When you received the money in your home country it was income, you paid tax for it and the part you did not spend are from that moment on savings from the view of your home country.