@jurgis.zagorskasW6FX3
Linking an IFC file into a Revit view can take a long time because it is primarily a CPU-intensive process, and Revit is mostly single-threaded for many operations, including parsing and importing IFC data. If the exported IFC files used High LOD when they are complex with lots of geometry and metadata, which need to be converted into Revit elements, then it is normal that it hangs for a while. Revit has to map IFC classes to its internal categories, which takes processing power.
Morever, i fit contains complex geometries which are non-native to Revit, especially meshes, can take longer to process. Nested elements (like families, groups, and assemblies) in IFC also add extra conversion steps.
So in short, it could be a 500Mb IFC and opens in 2 mins and it might also be a 50Mb IFC that takes 2hrs to open