@Christian ********
, contact the Thai embassy, and ask them about studying Thai in Bangkok, and ask them for suggestions on how to do it, but, do not tell them about your girlfriend. Tell them a potential job in the future would require you learning to speak and read formal Thai. Do not tell them which company out of privacy concerns. You will need to pay for 14 days of quarantine, US$100,000 of insurance that covers covid-19, in order to get a certificate of entry from the embassy, if they help you, and approve you for entry, after you also contact a formal language school, and pay for 160 hours of lessons in order to get your ED extensions while you go to school, as the visa must be extended every 90 days with the documents the school gives you. You can do this for up to three years, as long as you go to school. If you do not go to school, then 90 days, if the Thai embassy allows you to enter. Most ligitimate schools cost around US$1000. Some are cheaper, some more expensive, but, with this virus, many are not open. Good luck. It will cost you around US$4000 just to get here, and finish quarantine.