We did the same and our VPN worked fine then and works fine now on Big Sur. If anything isn't working for you, then I feel like that's your fault considering th

We did the same and our VPN worked fine then and works fine now on Big Sur. If anything isn't working for you, then I feel like that's your fault considering that 32-bit apps have been deprecated for years and kexts that were incompatible have been deprecated (and messaged) since at least Catalina. You, and whatever vendor you used, have had multiple years to prepare for the changes in Big Sur that would break this stuff.