Indeed, I practice and teach the Wim Hof Method and Wim Hof breathing ticks all the boxes for a potential endogenous DMT release, yes! Apparently it has been challenging so far to scientifically prove a direct link with increased DMT levels, BUT:

"The Wim Hof Method combines specific breathing with cold exposure and mental focus. It typically involves 30-40 deep breaths followed by breath retention until the urge to breathe returns, followed by a deep inhalation with brief holding.

Research has documented remarkable physiological effects, including voluntary influence over immune response. While not explicitly focused on DMT release, the method creates conditions that could influence endogenous compounds. [...]

Many practitioners describe experiences remarkably similar to DMT effects:

- Visual imagery, from geometric patterns to complex scenes
- Sensations of energy moving through the body
- Altered perception of time and space
- Encounters with seemingly autonomous presences
- Access to what feels like more profound knowledge
- Dissolution of identity boundaries

These experiences typically emerge after 15-30 minutes of sustained breathwork and may last throughout the session."

https://www.alysebreathes.com/knowledge/breathwork-articles/dmt-release-through-breathwork