So I took another look, and I only found 1 thing that I’m not sure is causing your issue, but may.
In your second picture, where you’re calculating the projection weights, your InverseLerp node doesn’t appear to be clamped, but VisualTechArt’s is.
If you click on the node, there should be settings in your details panel allowing you to clamp the value. I only skimmed through the video and I don’t know what that value should be clamped to, you’ll probably have to re-watch it.
Given it’s for projection weights, it may be what’s causing your issues. If not, could you send some screenshots of your problems? There’s no way I know of to import .uasset files like the material you’ve shared, so I can’t get my hands on it.
Other than that, I didn’t notice any other issues. Again, I’m knee-deep in my own never-ending Unreal struggles right now, so my attention is kinda divided. 