Just noticed the new requirements are listed on the US Embassy Thailand website now as well:
COVID-19 Information - U.S. Embassy & Consulate in Thailand (usembassy.gov)
Are U.S. citizens permitted to enter? Yes. From July 1, 2022 onwards, travelers entering Thailand will no longer be required to register on Thailand Pass. They will be subject to new entry measures as follows:
Entry Measure for Foreign Nationals (From July 1, 2022)- Thailand Pass not required
- Certificate of vaccination or an RT-PCR/Professional ATK COVID-19 test result issued within 72 hours before departure
- Medical insurance not required
- Airlines will check your documents. Disease control officials will conduct random checks of these documents upon arrival.