For others and future self looking to add a remote that requires a browser, like pcloud.
I was stuck using an iPhone for the moment. Adding the remote on my raspberry pi with ssh access worked by using ish on my iPhone. I have rclone installed there as well and first did
rclone authorize “pcloud”
I then opened the url in my browser on the iPhone and waited some time. After I switched over to ish and back I was presented with the page asking if I wanted to allow rclone access and chose affirmative. Switching back to ish I got the result I needed and copied it in the “rclone config” step that asks for the result of “rclone authorize”. I only started “rclone config” after I got the result from “rclone authorize”.