You have to look at whether either are them places are suitable for a large family.
Hua Hin is a retirement town and Chiang Mai is more rural and quiet.
Do they have substantial international schools compared to where you are from? What’s the reason for moving? Will you make more money or is it a move for other reasons?
Haha not stress free. They’ll question you at the border if they feel you are only staying in Thailand and not travelling like digital nomads are supposed to do
It’s not a year old yet. Any changes will come after. There have been more rejections than you think.
Only 20,000 DTV visas approved as of February. Nothing compared to the number of tourists that enter each day, or the amount of work permits approved for expats