Intervention vs control groups + desktop vs mobile content

Hi,

I am struggling to understand how to use a combination of branch, display logic and the survey flow tool to achieve what I need.
My survey requires the last block to show a different variation of the same text to each group (intervention vs control). In addition, the last block will also need to be reworded differently depending on whether the user is on mobile or desktop as
i) the mobile version will lead to an app download (link intervention or link control)
ii) the desktop version will remind the participant to check their inbox and open the link (link intervention or link control) subsequently on their mobile.
Q1 - is the randomiser tool only for varying the order of contents, or can it help me ensure 50% are assigned to a control group and 50% to a intervention group?
Q2 - can anyone please advise me as to whether the survey flow I've produced in the attached screenshot accomplishes what I need to achieve?
Thanks so much!