I don’t know how big a hit that indirection with symbolic links causes. It’s going to depend a lot on what gets cached, the drive type and speed, how hard and often FS2020 accesses files through those symbolic links, etc.
The ideal would be to have all files accessed directly and there may be fewer issues than with non-standard locations. However, once I found the UserCfg.opt edit, I’ve had no problems.
Another consideration, especially after the recent FS2020, Windows, and Nvidia driver updates, is how many are having to rebuild and repair Windows to mitigate or solve various frame rate issues. Windows has shown, at least to me, that it’s still fragile and blowing it away and rebuilding it fresh from a new windows.iso file is occasionally still required. I just did that (again) so I could finally update to the new Nvidia drivers. If my FS2020 install had still been on the C drive I would have had a much more difficult time rebuilding everything and much more downloading or backup space required.
Windows itself doesn’t seem to be ready to count on being stable if recent performance is any guide. With FS2020 on another drive, I was able to be back flying after just redownloading and installing Steam, reconnecting the FS2020 path, and editing the UserCfg.opt file. (Tell Steam you want to install it and point it to where FS2020’s Steam directory is and it finds everything already there - and reconnects any other Steam games in that same repository.)