[Ristovski]

They seem to go up to 4 :)

Example: https://github.com/UCYT5040/Google-Sticker-Mashup-Research/b...

Edit: 6: https://github.com/UCYT5040/Google-Sticker-Mashup-Research/b...

[cobertos]

Both examples are still two emoji. In the first, the second emoji is the combination of u1f62e and u1f4a8 via a zero width join (u200d) to form the exhaling emoji glyph. Explained more here https://emojipedia.org/face-exhaling/