Dev beta 1 just came out this week for Mac OS Ventura. It seems something changed or broke with client VPN. L2TP no longer works. If anyone else here is a Apple dev tester and finds a solution to get client VPN please let me know.
Btw, I did post on the Apple dev forum and submitted feedback to Apple. Hoping they have a magic fix or I'll be rebuilding two Macs 😞
I am not surprised VPN is broken, historically I've found Apple doesn't add in full support during first few betas, I'd say be next release they will have it working.
I'd never recommend running a BETA on a production machine as you are always in for a world of hurt. Usually the gold master is buggy, I normally wait until at least the first update is released because by then all of the early adopters have found most of the bugs and then fixes / work arounds are available.