Starting in Big Sur, Apple requires a local user to explicitly allow kernel extensions to be installed, even if they are whitelisted by MDM policy. By default only admin-level accounts are permitted to do so, but this is not practical in environments that don't allow end-users to be admins. Any such kernel extensions, and the software that depends on them, are basically unusable after upgrading to Big Sur.

Please implement the new 'AllowNonAdminUserApprovals' option in macOS Kernel Extension profiles. This will allow our non-admin users to "approve" the required kexts and their software to function again. The public documentation hasn't apparently been updated, but it was announced here https://support.apple.com/en-afri/HT211860 and has been implemented elsewhere.