Is this balanced?

I am working on making a tanking focused subclass for fighter. I wanted to ask if this is balanced or not;

Juggernaut's plate

You can spend a long rest and adequate materials to attempt to modify a set of heavy armour into juggernaut plate. Juggernaut plate is massive, Heavy, imposing, and immensely durable. It is heavy armour with a strength requirement of 16 and a constitution requirement of 14. If you fail to meet the strength requirement, your speed is halved and you cannot jump. If you do not meet the constitution requirement you must make a constitution save(Dc 12) every hour or gain a level of exhaustion. Juggernaut plate has a base AC of 20 and reduces all damage taken by your PB, but imposes disadvantage on all dexterity checks and saves. Only a juggernaut can wear this armour.

Armour smith

You gain proficiency with smith's tools and your proficiency bonus is doubled when making or maintaining armour.

Bull rush

When you move more than 10 ft towards a target you can both make an attack and throw them 10 ft in any direction

Body block

Whenever an ally within reach becomes the target of an attack, you can take a reaction to put yourself in the way, taking the damage for them. When you do this, the attack automatically hits and the damage from it cannot be reduced in any way.

Steel titan

Your size increases by one category(Med->large, small->med)

Your reach is increased by five ft.

You have advantage on STR. checks and saves.

Your health is increased by 2 for every fighter lvl you have

You cannot wear any armour other than juggernaut plate and all clothes have to be specially tailored to fit you.

Indomitable beast

You gain the following features:

You are immune to critical hits.

Your armour becomes indomitable juggernaut armour and has a base AC of 28, reduces all damage by twice your PB, and gives disadvantage on all dex saves and checks.

You cannot be restrained, stunned, or incapacitated and you are immune to the frightened condition.

You have advantage on death saving throws.

What levels are all these for?

No, it's not balanced that capstone is way too powerful. Similarly the Juggernaut Plate is too powerful at level 3 and not powerful enough at level 15.

Bull rush is either too powerful or not powerful enough depending on what action is required to make the attack it provides and whether that attack also deals damage.

Steel titan ok but in some contexts could be a problem. In a pre-made dungeon, often a Large creature doesn't fit on the map and either has to Squeeze which is really bad if you are in combat or ends up creating cover for the enemies. Being a Large creature can also be in issue for things like Flying Carpets, so being Large is often not an advantage which is why many classes / features just give it as an option to temporarily become large.