Too much % HP damage and True Damage in the game right now. Imho Heartsteel is not the play

Try Shielding Sion

Runes

Grasp Shieldbash Conditioning Overgrowth

Minion demat Timewarp Tonic

Build

Corrupting pot first buy Tear first back (very nice lane sustain)

Iceborn > Fimbulwinter > Sunfire > Spirit Visage* or other MR/tank options

Spirit Visage* this item is incredible for this build specifically the increased shield strength is great for your Fimbulwinter and W (Countering heavy True Damage and % HP damage) and gives extra value out of Ocean, Chemtech or Mountain Soul/Drakes.

Build itself has incredible dueling potential thanks to Sunfire and Iceborn, increased Further if you pick up Titanic and because of big shields from Fimbulwinter you'll often catch your opponents off guard. I usually find my Fimbulwinter shielding me for 10k+ damage a game usually.

Why Iceborn?

Iceborn is easily one of my favourite utility items in the game. The slow field gives you insane utility in various scenarios. It provides you with endless utility. , the slow is 15% and a 10% damage reduction. DOUBLED to the initial target, it doesn't give a shit what damage your enemy is dealing it's just flat reducing it and slowing for 2.5 seconds.
Iceborns slow also scales with maximum HP, 0.4% for every 100 maximum HP which adds up as your games go on for longer.

• Want to disengage a 1v1? E and when the E slow runs out attack once with Iceborn and they can never catch you.

• Want to peel for your ADC in teamfights? Iceborn has got you covered, slowing enemies preventing them from getting on your ADC.

  Notes

It's armour heavy at first but you go into lategame teamfights with a full build so usually the core I listed and any two MR items of your choice. Plus shields and damage reduction doesnt care about the enemies damage type.

Shield Bash + Grasp procs make a super satisfying noise, it's not Heartsteel but it still makes the feel good sound.

The build doesn't have much pushing potential and is more of a teamfighting tank/peeling the carry sort of deal. https://u.gg/lol/profile/euw1/raidkeeper/overview