I'm sorry for the late reply. From our side, to avoid the slowness, we have tried to reduce the resource consumption by some intensive processes. This should be done automatically in the background. During the initial full system scan, if you feel that it slow down your machine, you can set the full system scan speed to slow, so that it will give up more resources, which at the end will speed up the machine.
One of the most common reason of slowness is lack of memory. In this case, we will advise to choose only 1 offline antivirus engine, either from SecureAPlus or other third party antivirus that user preferred. If users have their own preferred third party antivirus engine, we will advise the user to turn off ClamAV from SecureAPlus.