If your hard drive isn't fast enough yes, your game will take a while to load. If you have a ton of CC then it will definitely take ages. You should always make sure you are using a decent drive and connection before attempting to move the game installation and Electronic Arts folder to the external drive - https://bluebellflora.com/2023/11/26/choosing-an-external-hard-drive-for-your-game/
For thorough instructions on how the symlink works and issues with it please see my original guide here - https://bluebellflora.com/saving-your-sims-4-folder-to-an-external-drive/
For CC issues head over to the Mods/CC forum - The Sims 4 Mods & Custom Content | EA Forums
