IF that is the stamp you got on entry: Admitted until xx March 2026 it became void when leaving Thailand.
Automatic gates do not stamp passports, if you love stamps, visit next time the Immigration booth and hand over your passport to an Immigration Officer.
"In Thailand, "work" has a very broad legal definition under the Alien Employment Act, meaning any activity requiring physical or mental effort, whether or not for wages or benefits, requiring a work permit for foreigners.
typing on a keyboard telling others it is not physical but for sure you need a special mental effort to be able to do it.