does private relay protect app use.

Hello newiphoneman,

iCloud Private Relay helps protect your privacy when you browse the web in Safari. For more information check this out: About iCloud Private Relay - Apple Support

Thanks.

Your banking, shopping, and medical apps should all be using secure connections already. Using private relay or another proxy or vpn service with them would be counterproductive.

I experience the same thing: my banking apps stop responding when I set on private relay mode, yet they resume normal operation when I turn them off.