Think of Kevlar. or composite materials. Magic doesn't have to be floating Fey armor that sucks life from your enemies.

The magic in my world has been around so long its just physics. Physics we don't have. This allows other manufacturing techniques and advancements in tech.

The body armor is made up of lightweight anchor material. that is made of compression layers that basically work like kevlar. It is supply at low "speed" and hardens when it moves quickly. Except its not a dispersion of force but instead a manipulation of time. The material actually lags behind real time for a moment, which in effect allows it to harden or not move. The projectiles force is dissipated over the whole surface area, and this energy actually fuels the magical time distortion.

This works great for relatively "slow" and heavy weapons. knives, spears, arrows, bolts, slower / heavier bullets. The armor begins to fail when the kinetic energy is based more on speed than mass in the Force = mass x acceleration formula.

This means low mass high speed projectiles.

To counter this weakness there are many layers of compressed air that extend from the armor in active mode. This is inconvenient as the user is basically in a giant bubble where layers of air run vertically so the user is edge on to the layer. This works to slow low mass projectiles through friction and compression of the layers.

It's the difference between shooting a phone book in the cover (using the layers to disperse force laterally.) and shooting the phone book in a vice on the edge where all the paper come together. The projectile traveling between the compressed layers loses energy to friction.

This bubble armor was the staple for almost a decade until the North-Pass war, where a major flaw was revealed and exploited.

A soldier still needs to advance on their feet.