Iphone 15 as bike computer???

ok im debating on buying a garmin 1040 or the new element v2, but before i do i been researching a cheaper way to replace my old bike computer with my iphone 15 and my apple watch.

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so my question is with my current bike computer i can use my shimano Di2 and see what gear i am in could i see this same information with my iphone?

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i have a gamrin varia bluetooth headphones apple watch, speed and cadence sensor, and power meter pedals all connect to my iphone.

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will i be losing something by ditching my bike computer and using only my iphone other than lose knowing what gear i am in?

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are there any memebers on here running a phone as their main computer with power meters, garmin varia, headphones, shimano di2, speed and cadence sensor?

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