ok thanks. Strange it doesn't work for me. I have a switch in between router and PS5 and a guest wifi network. Maybe one of these two causes the problem?Yes; the key is both of them have to be on the same network.
My PS5 is connected to the router via LAN cable and my phone is connected to WiFi. When I performed the initial scan, it picked up my PS5 quickly. Afterwards, each time I start the app I see my PS5 already there.