When you open the file from File Explorer you need to wait for SketchUp to ping the license server and then load extensions before even starting to open the .skp file. With File>Open in SketchUp, the license checking and extension loading has already been done so you don't need to wait for that. So that difference is going to account for part of the time delay.
@unknownuser said:
The files I'm referring to are located in server
What if the file is located on your local drive? Does it still take the same amount of time to open?
@unknownuser said:
I'm using Sketchup Pro 2021
@unknownuser said:
I hope this can be fixed.
At this point in time you can pretty much expect there will be no further changes in SketchUp 2021.