At the moment, bigtechs in Europe rely on cooperation with banks for the settlement of payments. A payment made using Apple Pay or Google Pay is mostly settled via the credit card stored in the wallet, but issued by a bank. The next step could be to create closed payment systems that are no longer based on established payment instruments and actors.
The idea here is to issue one's own "platform money", notably in the form of a "stablecoin". The most prominent example of such a concept was probably the Diem initiative (formerly known as Libra) launched by Meta. Stablecoins often peg their value to an existing currency or to a currency basket. Moreover, their value is backed by suitable collateral.