Anything special about that component, such as part of an asmdef?
What about if you right now made a fresh prefab using the component (in its proper namespace)… does that work?
If so you can open the good new prefab and the one that’s failing and look for the GUID of that Component, see if there’s something untoward about it.
As you probably already know based on your post above, here’s my standard knowledge-dump:
Some info about Missing script warnings, GUIDs, renaming GUIDs, etc:
EVERYTHING in Unity is connected to the above GUID. It is super-easy to inadvertently change it by renaming outside of Unity. Don’t do that. Instead:
close Visual Studio (important!)
rename the file(s) in Unity
in Unity do Assets → Open C# Project to reopen Visual Studio
now rename the actual classes, and MAKE SURE THE FILE NAMES DO NOT CHANGE!
If you are NOT using source control while you do this, renaming files is an EXTREMELY dangerous process. Use source control at all times so that you can trivially revert if you miss a critical step and damage your project.