вариантов вообще-то нет

То есть как это?...
Я знаю как минимум один:
I gonna turn 30 in September

Точно! I’M gonna…

Ok, got it

But bear in mind that always SAY gonna, but rarely write it.

Yes, I will use it in convrlersational English only)
...
What about the 2d snippet about Raj?
Maybe there are some difficult phrases, should I explain them?...

As far as GONNA, in speech you can use it in ANY situation — it sounds perfectly natural. The same with WANNA. It just looks silly to write them unless you’re purposely trying to be funny. Imagine writing патамушта everywhere. It would look like hell, but it SOUNDS perfectly natural.

Wait, I thought I translated Raj. Where did it go?

Oh, it’s a different one 👍🏼

Yep, there is the end of this story)