@AMock
Yes - you can check to see if there is an out of office message.
To do so, use the Office 365 Outlook Get Mail Tips for a Mailbox action. Use a condition to check if the Message from Dynamic properties is empty. If it is not, then there is an out of office message and you should assign to another approver.
Use the approvers email as the input oto the Get Mail Tips action
I will post a screen shot of an example later tonight.
If this answers your question, please mark your post as solved.
Scott