If there’s something epic in Unreal that is the bugs.
The only thing I’ve managed to get working is to make ALL the materials again.
If another material breaks, I’ll jump out the window.
I thought about downloading UE5.6.
But after reading the comments from people who have tried it, I think that a downgrade would be a better option.
They should consider changing the company name to EPIC BUGS!!
Is logic they do not sale it… each five minutes you have a new bug…
You are more time fighting against bugs that developing your game…
Other bug:
it broke the normals of my static mesh… the material is applied in the internal face
I was using this mesh since a year ago… UE5.5.4 is the wors version ever 
Best Regards!!