Coming in on a non-Schengen flight you will always have to go through passport control of course, then through baggage claim and back through security upstairs to connect. You could potentially do that in an hour with hand baggage only if you hustle and everything goes smoothly, but it is risky as noted above.

Arriving from Schengen it's going to depend on if your flight gets to park directly at the terminal or if you're stuck with a bus gate. The bus will take you to baggage claim and you'll be in the same position as above (aside from passport control). If you walk of the plane into the terminal then you can stay airside the whole time.