Last Sephirah Meltdown

[Khalani]

So I'm on day 45, only have the extraction team meltdown left but I can't do it and have no idea why. I made all missions and the last requirement was to get the department to level 5.
Is it impossible to do all in one run? Day 46 will be another imprint day where I can't do it, right?

I feel that I'm missing something...

[Folex]

Once the conditions to unlock the core suppressions is met, you need to beat the day to get the core suppression. Since beating the day would lead to going to Day 46, you'll need to restart from Day 1.
In order to do all of the core suppressions in one run, you have to unlock both Record and Extraction team simultaneously so that you can fully unlock one department to get the core suppression, then memory repository to fully unlock the other. Otherwise, the situation you're in would happen.