There are lots of threads about this already, including that specific program, and the summary is that Opus (and most other things) will usually copy to the limits of your hardware, unless the hardware has quirks or there is something unusual going on. Sometimes one program is faster for some people’s hardware and the files they are copying (and their antivirus and every other factor) while the same program may be slower for others. Often it’s down to testing things properly, which is more complicated than you might expect with file copying.
The copy buffer and non-buffered I/O settings under Preferences / Miscellaneous / Advanced can be used to tweak things for certain scenarios.
Usually claims that one program is faster than another are really due to not testing properly. You need to ensure both programs have the same per-file overhead (e.g. copying attributes, timestamps and permissions), and you need to ensure that one program is not copying out of the filesystem cache after the other program put the data there.
You should also compare the time shown in Task Manager for the disk activity to start and fully stop (there may be a delay and spike at the end), to get an objective measure. Progress dialogs do not always measure time or speed in the same way, and in some programs close before the data is really flushed to disk.
If you think Opus isn’t copying at full speed, we need details of the exact situation, and to be convinced you’ve tested things properly, as threads about copy speed are almost always a waste of both our time and yours. They do sometimes reveal a situation where we can improve things, so we are not completely closed to the idea or saying Opus is perfect, but you need to post more than “x is always faster than Opus”, as that suggests you haven’t really investigated things.