WOW, don't admit you are working, no options for Digital Nomads.
It seems some experts never did read any of the Immigration Visa rules.
The Non Immigrant B visa allows everybody to work inside Thailand in combination with a Work Permit, the ideal combination, You can tell every body you work, you contribute into Thailand with paying tax and you have social security,
And the biggest benefit, you do not have to leave Thailand as long as you work, as each and every year you can apply for 1 year Extension of Stay based on working in Thailand at your local Immigration Office.
Live can be so easy and legal if you just pay a little attention to the rules.
OR just apply for the Single Entry Non Immigrant O visa based on being married to a Thai National, get 90 days on entry and extend once with another 60 days based on visiting Thai family. 150 days without bouncing and using visa run companies.
I know I like to give visa advice, not how to avoid buying a visa.
And another one who ask a question without the most important detail, it all depends on the country of origin of your passport,
But you can go to apply during the last 30 days of your Admitted until period stamped on entry into Thailand, NOT the expiration date mentioned on the visa,