Your TV is waiting. This takes a minute.
On the PS5: Settings › System › Remote Play › Link Device
Use a second account, so you can keep playing on your main one.
aSign in with the spare account. Do not create a new account on that page.
bWhen the page only says "redirect", copy its full address and paste it here.
You can put your phone away. Press Done on the TV.
Encrypted end to end. Only your TV can read it.