Skarner feels like a tank that cant tank

I really want to like skarner but he just feels so awful to play. He has max health scaling on all his abilities minus ult, most builds have you get hearsteel first yet his armors suck. Enemies only have to build ruined king and I just feel useless afterwards. I try and tech into armor but it just feels like it does nothing for me until I have full build. His kit feels very deceiving with his passive, w, and q it feels like he is built around locking someone down and outlasting him but again any one max health damage item just seems to completely neuter that. His W shield is the most pitiful tiny shield I have seen any ability grant even with spirit visage it barely gives you a couple hundred shield health even late game.

I feel like I'm doing something wrong but I can't tell what. I engage with e, use q and w to lock targets in place then r to pull them into my team once they are low enough to be jumped but past the 10 minute mark I feel useless until I'm full build. I usually build hearsteel, despair, spirit visage, thornmail, jak'sho. Somewhere I can tell im doing something wrong but I usually cant tell what. The biggest thing I have noticed is that the enemy jungler just cooks me on objectives every game because their clear is just so much faster.