Material blend mode: lighten only alternative

I have been playing around with the idea of creating glowing buttons for my menu. UMG does not allow emissive textures so unless I want to use 3d widgets I’m stuck using materials.
So I made a button texture and made a glow texture for it as well.

Tried it with translucent blend mode and it looks nice. Unless you color the buttons. If your color is not something extremely bright then you will most likely come across a situation where the background is brighter - thus your “glow” is actually darker.

Tried it with additive and it looked nice after lowering the opacity except that for me it’s the exact opposite of how a glow works. As in on a black background it is barely visible if at all while on a bright background your eyes melt. Real glow actually seems brighter in darkness while barely noticable if at all on a bright background.

What would actually work pretty well (most likely) is Lighten Only blend mode (or at least that’s how Gimp calls it and I think PS as well) but I haven’t found a way to circumvent the lack of such mode for the materials.

I would love it if there was something like the coordinate expressions that handle information perpixel - so I could make the material calculate the results based on what it is rendered above/over/upon.
Is there a way to control blend with background inside a material blueprint or do I have to implement Ligthen only mode with C++ by hand?