Any details about the boundary conditions between the two 2 stacked beams and the material properties?

wouldn’t the result be the same since it is h/2? if the two beams stacked each have h height then it would be 8 times stiffer than the one beam, I guess?

Single beam… I ~ h^3

Stacked beam… I ~ 2 * (h/2)^3 = 2/8 h^3 = 1/4 h^3

Deflection is inversely proportional to I, so the stacked beam will be 1/4 the stiffness of the single beam.