Same issue here. Right-clicking in the event graph takes about 6 seconds to show up, causes entire program to hang in the meantime (rest of UI becomes unresponsive) which indicates to me that the lookup code is running on the UI thread. Unreal 5.2.1, Win 10, AMD Ryzen 9 5900X, NVIDIA RTX 2070 Super, 24 GB RAM (13 GB free).
First time using Unreal so don’t have anything to compare to except for YouTube vids.
The freezing behavior happens anytime the menu is being shown, so it also hangs for ~6 seconds when just trying to i.e. “promote to variable” after dragging off a pin.