Could you elaborate? I've used Zelle in the exact way you've mentioned previously (entered a phone number and an amount to send straight from my bank app) with no issues.
Zelle was a consortium of the biggest US banks. It works fine if you have a deposit account at one of those institutions, or if you have created a Zelle account that lets them get you funds through a shim if your bank isn't a member participant of Zelle. If you're at a brokerage that doesn't support it, a credit union, or a community bank, your experience is meh or non existent.
FedNow is native real time messaging plumbing, so all deposit accounts can support it once you plug into FedNow (which is run at cost by the Fed). We should theoretically arrive at an experience similar to UPI, PIX, and other instant payment systems where you can use phone numbers, email, or QR codes to facilitate payments over the next 1-3 years.
Plenty of credit unions like BECU and First Tech fully support Zelle for sending and receiving payments, some credit unions even have higher daily and weekly Zelle limits than the traditional banks.
That's how zelle works as well, with the exception that it's probably not built into every banking app, considering the number of US banks.