70 minutes to transfer ZRH is plenty on such an itinerary.
I have even made Schengen-Non-Schengen transits at ZRH when delays shrunk the transit time to 25-30 minutes — it’s not a fun rush at that point but it was do-able. It used to be easier to do before Swiss passport control started taking me more than a minute or two in line (if even that), but now at times it has taken me as long as 10-15 minutes to exit Schengen there. I miss the days when ZRH used to just look at my passport covers and wave me in/out without opening the passports. I even miss the days at ZRH before they started to always swipe passports.
I still prefer ZRH over FRA, by a wide margin.