@W00kie Welcome to the forum!
It is not currently possible to disable this username obfuscation, but a work-around has been described here. Alternatively, you can just use Right-Click > Bitwarden > Auto-fill (which will display all account usernames in cleartext).
Bitwarden has promised that a future browser extension release will provide an option to remove the username obfuscation from the inline auto-fill menu. Until then, you will have to use one of the available work-arounds.