Material override -> fixed material -> use alpha
Material override -> fixed material -> diffuse -> alpha channel(A)
or
Material override -> shader material -> new MaterialShader
color col = color(1.0, 1.0, 1.0, 0.5);
DIFFUSE_ALPHA = col;
or
Material override -> shader material -> new MaterialShaderGraph. Create ColorUniform and connect RGB with Diffuse and Alpha connect with DiffuseAlpha.