***** NOT A TEACHER
*****
Hello, Takoyaki:
1. Most books give this "rule": The adverb "not" comes
before the infinitive. (My example: I try
not to eat too much ice cream.)
2. Most books also say that many native speakers often break this rule: I try
to not eat too much ice cream.
a. Why do native speakers break this rule?
i. As a teacher in this thread told you, it seems to emphasize the negativity.
3. My respectful suggestion:
a. While you are a learner, you might consider simply following the rule (especially on tests if you have a strict teacher).
b. When you become fluent in the language, then you can let your ear be the guide.