Can I change from a DTV to a Non-O retirement visa during the 5 years?

Yes, you can convert a DTV (Digital Nomad Visa) to a Non-O retirement visa in Thailand. This change can be made at your local immigration office just like other tourist visa conversions. Alternatively, you can cancel the DTV, enter Thailand on a Visa Exempt basis, apply for the Retirement Non-O visa which will grant you a 90-day stay, and then apply for a 12-month extension after approximately one month.