Steel Unit (2021)

Both shows are of the same genre - Survival Show and Competition. Iron Squad contestants are fit and determined military reservists. Physical 100 contestants also include military reservists.

Both shows involve teams that form a bond through their shared occupation and go through survival games that include physicality, strategy, and teamwork. The games aren't the same, but the growth and spirit of the members have a similar feel.

Both are military survival competitions, although the concept is a little different
Both have very similar drills/games/missions
I think The Soldiers was actually spun off from the Iron Squad because of it's success.
I think Iron Squad is much better imo as you get to know the contestants more, there's MC panelists, and more heart, but if you're in the mood for more military competitions, then try the Soldiers.