Hi Hendry,
My understanding is that you configured the Button trigger with several text inputs, then when you run the flow on Mobile app, you want to be able to select one of them from a selection list. If I misunderstand you, please feel free correct me.
To test this issue, I create a flow looks like below, when I run it on Mobile app, I found that I am not able to select the one I want to use and the flow finally failed. Are you getting the same experience with me?

I would suggest you submit an idea at Flow Ideas Forum, PGs will check this forum and take it into consideration in the future releases. I will also report this on my side.
Best regards,
Mabel Mao