How the hell do I make fluids solidify?

You know how in minecraft, water and lava sources collide to make obsidian?

I added a custom liquid, and I really don't like how it just flows over fluids in an ugly way, so I want it to be solidified into crying obsidian when touching it.

After making a small prodecure to detect nearby blocks of lava and water to solidify, I tested it and it didn't work. At first, I head no idea why; the code was flawless and it was meant to work.

Then I realized the disaster.

The tick update triggered procedure was only managed by the full source blocks, not the flowing liquid blocks, and so, the procedure was utterly useless.

Anyone know how to fix thi and make every flowing block solidify too? does anyone happen to have knowledge of how vanilla handles it, and is it replicable?