Is it possible to scale a mask texture applied to a sprite 2D? (Mask Shader)

Hi all!,

I'm still quite recent with Unity and specifically with shading, but I've been messing with an alpha mask shader and got it to work. This shader is applied to the sprite I want to be 'hidden', and I add a texture mask to make the sprite appear through the mask. However, I am looking for an effect where I can scale the mask and not have the texture scaled and fixed to the main sprite's size (for instance to make the hidden sprite gradually appear by increasing the radius of a circular feathered mask).

I've searched for quite a while now but nothing seemed to work. Is it possible to change a secondary texture scale related to a main tex?

Sorry if I'm not being very explicit, and thank you so much in advance for the patience and help!