@Tony *********
nope. As I said you can be tax resident in multiple jurisdictions...and that's the purpose of DTAs if you can only be tax resident under one jurisdiction as you infer there is no need for any DTAs is there ❓👍
Now if your income wasn't taxed at source, and you are under two jurisdictions then yes the second one could take the full wack
The concept is called taxed at source.
I have been under 3 tax jurisdictions at one point and the source of the income gets first bite and the tax credits against other two jurisdictions
BTW and not every country in the world uses 180 days as a tax residency rule either