@Recchan, I think you have misunderstood. I’ll take the time to clarify it, because it will be useful for others to know when Revolut eventually supports Apple Pay and Revolut customers start using Apple Pay on TfL.
Every time you create an Apple Pay card, either on an iPhone or Apple Watch, the Apple Pay card has a new different card number from the physical card and from any other Apple Pay cards (including previous Apple Pay cards on the same device). For touching in, touching out, daily caps and weekly caps, TfL looks only at the card number. Therefore you should always use the same card number during each calendar week. If you touch in with an Apple Pay card and then touch out with a physical card (which have different card numbers), then you will have two unresolved journeys. You should also avoid removing and readding a card to Apple Pay in the middle of a calendar week, as you will negate weekly fare capping, as the card number will change.
You wrote “TfL doesn’t cap to Apple Pay underlying cards”, which is not the case, as the caps work correctly on Apple Pay cards and physical cards in exactly the same way.
The only exception to the above is when you log into the TfL web site to view your journey history. You need to enter your physical card’s card number, expiry date and CVV in order to view your journey history for any Apple Pay card numbers. The reason for this is because it is very difficult for passengers to find out their full Apple Pay card number and expiry date (a tiny minority of merchants print it on receipts) and it’s impossible to find a CVV. TfL receives mapping from the card networks (Visa, MasterCard, American Express etc) of Apple Pay card numbers to physical card numbers. Therefore once you enter a physical card number, you can immediately see separate cards in your TfL account representing your Apple Pay cards on the same account. I do wonder how this works when there is no physical card, for example with Boon and Deutsche Bank.