Thank you so much for this clarification! I applied your advice and it works perfectly now.
I was initially confused in how to use RVTs for multiple levels.
I made one RVT for both height and material, all my levels now refer to these same two files. There is no longer any need to “update” RVT sample inputs on all my materials in each level since when the level loads, it overwrites to the same RVTs used by the previous level. Works in editor and in builds.