This is specifically about Apple Pay (and likely any tap to pay) with Debit Cards. This post is irrelevant to Credit Cards.
Simply put, if you want to avoid the tap-to-pay surcharge at any merchant, you must insert your physical debit card and choose SAV (maybe CR too). Even if your Apple Wallet shows "eftpos SAV" as the chosen network, the merchant is able to route your transaction via VISA/Mastercard and the surcharge might be passed on to you.
According to Up Bank's Support, the RBA has removed the option for consumers to choose the network when tapping to pay. You can still choose the network when inserting your debit card but obviously that does not work for Apple Pay (and possibly for Google Pay too) and any time you tap to pay.
Similar information here https://www.easystreet.com.au/news/important-changes-to-appl…
Detailed at Apple Support, updated September 19 - https://support.apple.com/en-au/118269