I have been doing & I have done

[أسمـــاء]

I think that’s depend on what the tense which you mean ..
If you mean the past perfect passive .. you should say "I had been thinking that I wanted"
but If you mean the present perfect active passive you should say "I’ve been thinking that I want"
It’s like this as I think >> I hope that I was useful for you ..
& THANK YOU SO MUCH ^^ !

I'm sorry but I don't think that would be a structure commonly used in English
we can possibly say

Besides , you said past perfect passive but it's past perfect continous
and the other one will be present perfect continous as well

About Nuha's question
I'll try to look deep into it and get it to you

Peace