Yes — shorturl.in.th supports native Unicode Thai characters in URL slugs. Just type Thai in the custom alias field:
shorturl.in.th/โปรโมชั่นworksshorturl.in.th/รับสมัครงานworksshorturl.in.th/ทำผมworks
Uses RFC 3986 percent-encoding + Unicode NFC normalization. Browsers display Thai cleanly. Google indexes normally.