[2021] Copying data from another computer doesn't work (no character)

Hello,

Character data is not stored in the Windows Registry, and we do not recommend modifying this manually in any way, as doing so can potentially prevent your computer from working properly.

The best way of using the same characters on multiple devices would be Steam Cloud. As you say this does not work for you, try disabling it (either globally or only for Last Epoch) on the new PC, ensure it is enabled on the previous PC, and then re-enable it on the new PC. If that doesn’t work, does a character show up on the new PC after first logging in on it on the old one?