why is it that dsp2 hybrid orbitals have sq planar geometry while sp3 have tetrahedral? However, both have 4 orbitals.

Tetrahedral is sp³ and Square planar dsp².One example is Ni(CN)4  is square planar (evidence is from the fact that it is diamagnetic). Ni²⁺ has an electron configuration of [Ar] 3d⁸ and its orbital diagram is (in this case it is the excited state of Ni²⁺) so the 3d, 4s, and 3-4p orbitals are available for hybridization, which results in the hybridization dsp².

What determines whether a four-coordinate transition metal complex is tetrahedral or square planar is the number of d-electrons in the central transition metal. If the metal has eight d-electrons, as is the case for Pt²⁺, it is energetically advantageous for the complex to adopt a square planar geometry. In this case, the eight d-electrons will achieve some stabilization in energy by occupying the dzx, dyz, dz², and dxy orbitals