This might be a regional difference, but when I say it out loud, ‘tryna not kill myself’ is by far the more natural construction. But I agree that in writing, ‘trying not to kill myself’ feels more natural, while ‘trying to not kill myself’ feels stilted and intentionally awkward. Man I love language.
I think there might also be a subcultural difference, too, because there are different types of “tryna” that are used by different groups of people, and maybe being used to a more versatile “tryna” would make “tryna not x” more natural to speak.
Tryna A: “I’m just tryna screw in this lightbulb,” “I’m not tryna hurt you”
Tryna B (expanded tryna, not spoken by everyone, mostly skews younger and bro-ier I think): “You tryna go to Taco Bell right now?” “You tryna chill tomorrow?”