Performance monitoring controlled from console:
Stat Commands in Unreal Engine | Unreal Engine 5.5 Documentation | Epic Developer Community
“Slate” is the Input and widget system under UMG, the “UI” you design in blueprints as widget assets.
Slate is known for some odd behavior and performance drain (for example, the entire hierarchy of invisible and removed widgets still causing cursor events). Can’t tell if there’s anything going on without further info though. Some user behavior like opening / closing widgets rapidly already gives behavior like the above. You can monitor that with the Slate stat command.