Layered materials, with their distinctive electronic and surface structures, have garnered significant attention in catalysis and energy conversion research. MXenes, a family of two-dimensional transition metal carbides, nitrides, and carbonitrides, exhibit remarkable electrical conductivity and surface chemistry. MXene restacking is commonly observed property during the exfoliation process. Druffel et al. synthesized 3D Y2CF2 MXene through a high-temperature solid-state reaction. We performed density functional theory (DFT) computation to study the structural and electronic property changes when Y2XT2 MXenes formed bilayer and 3D structures. We considered X as C and N, while surface termination T as O, F, and Cl. Except monolayer Y2NO2, the other two Nitride monolayers show metallic character. Our calculations show that Y2NO2 monolayer become a metal when stacking occurs to form bilayers and 3D structures. On the contrary, all the carbide monolayers exhibit non-zero band gaps showing they are semiconductors. Their semiconductor character is preserved even after stacking occurs. Our HSE06 hybrid functional calculations reveal that monolayer Y2CO2, Y2CF2, and Y2CCl2 have band gaps of 2.27, 1.82, and 1.77 eV, respectively. Upon formation of bilayers, the band gaps shift to 2.55, 1.94, and 1.72 eV, while 3D materials exhibit band gaps of 1.98, 2.00, and 1.65 eV, respectively. Moreover, we also studied the electronic properties of bulk MXenes under the external pressure range of 1-10 GPa. Under external pressure, our calculations shows that the band gap change of Y2CO2 and Y2CF2 bulk MXenes is negligible. Conversely, increasing external pressure leads to a reduction in the band gap of bulk Y2CCl2.