I watched the WWDC presentation and paused the video to see just enough: Apple have ported their apps for Apple Silicon and there was definitely a Server icon there, but interestingly no AirPort Utility.
I can almost guarantee you that Big Sur will not fix this VPN issue and I suspect it will break even more services;
There will be more stringent protections of the operating system storage location which will likely prevent editing configuration files for the POSIX services. I was also interested to see the promotion of virtualisation for Apple Silicone and Big Sur. A demonstration included Parallels Desktop running a Debian 10 virtual machine along with the explanation that developers can start a web server in Linux and see it in Safari; this is significant because web services were included in the macOS Server migration guide before the release of macOS Mojave.
Using Parallels Desktop Pro you can run entire operating systems as a system service that starts when the Mac boots, so this would seem to be the preferred way to run servers on a Mac. If you bridge the network for your server vm it appears on the as a separate machine with its own IP address.
I am seriously thinking of getting an Apple Silicon Mac mini when it is eventually released to run all my servers in virtual environments to reduce power consumption. macOS Big Sur and a virtualisation solution might be like having your own little Azure: just make sure you've got plenty of RAM!
