I contacted NCH again on 12/24/20 and this is there temporary fix. It works with Big Sur. You can try now using the latest version from here: http://www.oldversiondownload.com/oldversions/soundtap-6-25-2020-12-11(intel).zipThis version is compatible with the Big Sur OS. Please contact NCH if you have another concern.
My Note: You need to completely delete your old version of Soundtap and Install this version as new install. Its now Ver. 6.25 Make sure to restart so it picks up virtual driver now.
I have verified it does work and record just like before.