Unless you have a very very old iPad, it should be able to work directly from Bluetooth. That’s what I do and it’s worked very well for years. No need for the ANT dongle - if you can even get that to work.
I use tr on an iPhone 5s and occasionally an iPad 4. I have a wahoo speed/cadence sensor, polar hrm and quark dzero power meter and they all connect perfectly using the native Bluetooth. No need to worry about ant+ or dongles at all.
Any particular reason you want to use ANT+ rather than Bluetooth? As others have indicated, the latter can be done directly, the former requires an adapter that may or may not work. Your power meter being BLE/ANT+ bilingual, the only reason I can see in your setup not to use BLE would be an HR sensor; it may be simpler to get a BLE/ANT+ HR sensor than to make ANT+ work on iOS.
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