Keep in mind all this kind of stuff can make the model less capable. If it has to think in "plain" English, it may well be squashing quality of code etc output.

I'm not sure how true this is, but when using "forced" json output it def had a big drop off in quality - https://arxiv.org/html/2408.02442v3.

I think you're better not fighting it with hacks like this and find a different model.

Changing output style shouldn't affect thinking at all.