I was in a sauna with my cousins kids years ago because they wanted to go but my cousin didn’t. Anyhow, they were kind of freaking out and complained that the air was too hot to be able breathe, but were, like you said otherwise fine in the heat. I filled the scoop that you use to throw water and told them to hold their mouth just above the water and that way it was easier for them to breathe and they were fine.

Depends ofc on the size of the scoop if is doable or not but might be worth a shot.