On the other hand, if you are on an extension for studying (just ED, NOT ED-plus), you need to leave Thailand once to enter on Non-B or as a tourist to proceed. Check your current stamp, and talk with your uni and new employer
, That sounds strange. You might get some other reasons. There are a lot of people in Bangkok who get a 60-day visit Thai family extension, then a Thai spouse extension and they are rather standard than exceptional. Those were already on entry on a Non-O visa marriage to a Thai or extension for the same reason, though.
"Completion of the TDAC will be mandatory for all foreign passport holders, including tourists, business travellers, and long-term residents. Exceptions apply only to travellers transiting or transferring through Thailand without passing through immigration control and to those entering using a Border Pass."
, you better talk with your local immigration office in advance. I believe you need an entry stamp on your passport that is used for an extension since your new passport was obtained outside Thailand. Basically, you cannot change foreign valid passports inside Thailand.
In that case, you have to get a new extension on your old (and "current" in Thailand) passport, which means your next extension is until the passport validity, 01 February 2026 instead of August 2026.
Or you leave and enter Thailand again on your new passport, at least one of the ways by air to switch passports.
, as long as you meet the requirements for Non-OA, ie insurance. As mentioned, you might need a new insurance policy.
A valid Non-OA gives you an earlier date of 365 days or insurance validity upon entry. This is the same you enter on the first day or last day of Non-OA. You need insurance covers for the length you want to be stamped in.