Tongue pulls back slightly from the T position, blending into R. Sounds close to 'chr'.

Americans pronounce troupe as TROOP (/trup/). In "troupe", the "tr" cluster blends into a "chr" sound — a natural American English pronunciation. This is called the TR Sounds Like CHR, a small move that separates 'classroom' from 'native'. It comes out as TROOP. You'll hear it in sentences like "She performs in a local improv troupe on weekends".
Record yourself saying "troupe" and play it back. The mic stays on your device — nothing's uploaded.
1 syllable, 4 sounds. Explore each sound's mouth shape and how it's made.
Tongue pulls back slightly from the T position, blending into R. Sounds close to 'chr'.

Curl or bunch your tongue without letting the tip touch the roof of your mouth. Brace the sides of your tongue against your upper back teeth, and round your lips slightly.
Round your lips into a tight circle. Let your tongue rest in the middle of your mouth, slightly raised.
Press your lips together to stop the air, then release. No vocal cord vibration.

The textbook way isn't wrong — it's just not how anyone actually says it.
In "troupe", the "tr" cluster blends into a "chr" sound — a natural American English pronunciation. /t/ shifts toward /tʃ/ ("ch"), so TR sounds like "chr".