Not all playlists labeled "full course" are created equal. Some are 4-hour "cram sessions" (great for review, terrible for learning). Others are 80-hour epics (great for depth, intimidating to start).
The story isn't without conflict. Cisco updates the CCNA exam every few years (from CCENT/CCNA 200-125 to the new CCNA 200-301). This renders old YouTube courses obsolete. ccna full course youtube