As Charlie mentioned, you would first need a suitable condition on the manager step to skip it under the appropriate conditions. Then the next challenge is that App Portal doesn't have a way of dynamically determining who the skip level manager is, so you'd have to hard-code the skip-level manager into the approval workflow steps. Since that would be different for every user, that isn't really practical. This use case (i.e. skip level manager or director/VP approval) comes up pretty frequently. I would suggest checking the Ideas page to see if any idea has been filed for this. If not, feel free to add one. If so, go ahead and vote for it and add your scenario details.
Having said that, there are potentially ways you could dynamically build the approval workflow with a script in the On Submit event, but this is tricky because there are no APIs available for managing approval workflows. You have to do some testing/research to figure out exactly what entries need to be updated in which tables in the database, so this option isn't for the faint of heart. Also, the user won't see the correct approval workflow during the checkout screens when using this method.
Anything expressed here is my own view and not necessarily that of my employer, Flexera. If my reply answers a question you have raised, please click "ACCEPT AS SOLUTION".
