How to compare lists in power automate and get the emails of the ones not present in one list

im trying to automate a checkin app to email a user when they aren’t signed in, and aren’t on the leave tracking SharePoint list. So I have to compare the checkin list and leave list, see who is not checked in, and then compare those that aren’t checked in to see if they are on the leave list. If they are not checked in, and not on the leave list, I want to retrieve their email and send them an email reminding them to check in. So far I get the correct people, but it sends them hundreds of emails, so obviously something in my loop structure is wrong