Why buy the inferior product, then suggests burying the inferior product.Spread the cost of a nest over 5-10 years and its pennies.
Why buy the inferior product? Get the doorbell too.
Go with Hive of that's what you have looked at, set it up for dual zone now, then down the line add individual smart TRVs so you have full control.
Nest straight away you would need to buy 2 to do dual zone. Then it can't be upgraded any more.