What should I do if the lattice parameters are different when using the build layer after cleaving two different types of crystal structures?

There is a problem in that the distance between atoms changes if one lattice parameter is unilaterally adjusted or an average value is used.

However, if the super cell is enlarged until it has a similar value, there will be too many atoms, which makes DFT calculation difficult.

Does anyone have any idea how to solve it?

The two crystal surfaces mentioned above are Pt(1 1 0) and TiO2_rutile(1 1 0).