The banking system in the US is a legacy mess. Transfers still take business days to go through and making your bank account # and routing information available is actually a security concern, honestly I don’t even know why that’s still a thing.
Products like PayPal and Plaid try to provide something that is slightly more usable, but with this underlying obsolescence their functionality is very limited.
When paying for services, credit cards are still the way to do it. For P2P payments, people use PayPal, Venmo, Cash App, and others. Nothing even close to a unified system like Pix in Brazil.