Frankfurt is a large airport, and you may have to walk quite a long way, depending on which two airlines you are flying. You will be going through passport control in Frankfurt, as you are exiting the Schengen area, but you should not have to go landside. Be sure to follow the signs for the appropriate terminal and concourse and *not* baggage claim! There is generally no security check when going Schengen to non-Schengen airside. One caveat: I have not been through FRA since the pandemic started. It's possible that they have made changes to the normal procedure in order to reduce staffing. Perhaps someone else can comment on that?