Thanks for the log file!
When you say the file display expands slowly, do you mean it takes a long time for the names of all the files and folders to appear, or for other details like the folder sizes?
Most of the Opus activity in the log seems to be it calculating folder sizes, which are presumably set to be calculated automatically and all the time on your setup. It's normal for that to not be instant, if the directory listings are not already cached by the operating system, but it should also happen on the background so you can see all the folders and work with them while the numbers are being calculated and updating on the fly.
Another detail I notice from the log is that the E:\ drive is extremely slow to respond when asked for directory listings. (This is affecting other programs that access it as well.) I'm guessing E:\ is a network drive, either over a slow link or on a very slow device (or possibly a non-Windows device running a badly configured version of Samba that is very slow to generate directory listings).
There's is also some activity from 3rd party components that may be worth investigating, but I'd stuck to the things above first and see if they are the cause. Try turning off folder size calculation, and eliminate anything that might causing access to the E:\ drive (e.g. folder tabs pointing at E:\ or below).