One approach we have used for multi-level approvals is a Do until that runs different approvals based on a switch (case) statement until either we get the final approval, or we get a rejected. Which approval runs next is controlled by a variable that each approval sets after it completes. If an approval sets the variable to "Complete", the Do until completes. You will need another variable to track whether the overall approval was rejected or approved.
Since the running approval switch case sets the next case to run by the Do until, it also allows an approval to be bypassed if it's not required for whatever reason.
I hope this helps.