@Elías *******
The point is that you are NOT making your money there just because you are a citizen there or because the company is located there, you are making the money from working in Thailand = taxable in Thailand.
20 out of 27 countries in the European Union has a double taxation treaty with Thailand, but I don't know for your country.
But the point is, that no matter how much tax your home country tax you, it doesn't magically remove Thailands right to tax the income.
If the work is done in Thailand and you are a thai tax resident (>180 days in Thailand), Thailand has the right to tax the income according to thai law.
And that is why the double taxation treaty is so important - it protects you from being taxed on the same work in both countries.
If there is a double taxation treaty, both countries are obliged to follow that treaty and their own country's taxation law is no longer the one in use.
If your country doesn't have a double taxation treaty with Thailand, then you might be eligible for taxation in both countries 🥺