From 1 October 2022 to 31 March 2023, holders of Danish and Lithuanian passports are entitled for Visa exemption on arrival to Thailand and can stay in the country up to 45 days.
Following the recent developments of lifting Covid-19 restrictions, and the emergency decree that has been in place since March 2020. Travelers entering the country will also not be mandated to test or show vaccination proof before entering the country.
The Danish Embassy in Bangkok has commented that out of a principle of caution you should still include vaccination documents when entering Thailand.
See the overview of Visa exemption rules here