Follow up: I threw together some Shadergraph versions of the Houdini Engine shaders over lunch. I didn't have a chance to properly test them, but at a glance they look equivalent, and since they're made in Shadergraph they'll work in URP.
https://drive.google.com/file/d/1Zbb1GzHym5nrncu6r3SsHpxCfkWurGkx/view?usp=shari...