If you spend more than 180 days in Thailand in a calendar year you are considered a tax resident. What visa you are or are not on is largely irrelevant (there are some explicit tax exemptions or limitations for LTR visa holders). It doesn’t matter if you aren’t there for 180 days consecutively it is all cumulative.

That being said, since DTV holders can’t legally work in Thailand, they’re realistically only really taxed on remittances and those are likely covered by a double tax agreement (assuming you paid tax in a different jurisdiction).

If you’re actually concerned about owing tax, you should probably contact an actual Thai accountant or tax attorney.