Just to put into context the "copy & paste" trick on the Fediverse:
- If your server has already noticed an account or post, you can search for it and interact with it totally normally without any copy-pasting.
- If your server hasn't noticed an account or post but you know it exists, you can make your server notice it by copy-pasting the account or post address into your server's search box.
Copy-pasting is just meant as a last resort for stuff your server hasn't noticed yet.