Another idea is the German letter Z — pronounced something like “tset”. You can make a letter or symbol larger by turning it into a sculpture. Here’s a quick illustration from ChatGPT:
Many languages have a letter to represent something like that sound.
- Z in German
- Ц in Russian and other Cyrillic scripts
- C in some Slavic languages that are written with Latin script
- Ț in Romanian
- צ in Hebrew
- つ and ツ in Japanese (tsu isn’t exactly ts, but the smiley face might make a good image ツ)